Related
This is a sample of my code. I want to have a 3 second delay before executing the next case (display picturebox). But When I tried using timer/stopwatch, the 3 second delay will only be on the 1st case and case2 will execute the same time as case1 (with no delay).
private void button1_Click(object sender, EventArgs e)
{
string input = (input1.Text).ToString();
char[] letters = input.ToCharArray();
int stringlength = letters.Length;
int length = stringlength - 1;
int state = 1;
int position = 0;
string validation = " ";
switch (state)
{
case 1:
//insert timer here
if (letters[position] == 'a')
{
pictureBox2.Visible = true;
validation = "Invalid";
label1.Text = validation;
break;
}
else if (letters[position] == 'b')
{
if (position == length)
{
validation = "Invalid";
label1.Text = validation;
break;
}
pictureBox2.Visible = true;
position = position + 1;
goto case 2;
}
break;
case 2:
//Insert Timer here
if (letters[position] == 'a')
{
pictureBox3.Visible = true;
if (position == length)
{
validation = "Invalid because it does not end at final state";
label1.Text = validation;
break;
}
position = position + 1;
goto case 3;
}
else if (letters[position] == 'b')
{
if (position == length)
{
validation = "Invalid";
label1.Text = validation;
break;
}
position = position + 1;
goto case 4;
}
break;
}
}
By the way, I can't use Task.Delay or async/await because I use the .Net 4.0 framework.
You can perform this by using:
System.Threading.Thread.Sleep(3000);
So Your code should look like:
private void button1_Click(object sender, EventArgs e)
{
int state = 1;
//some code
switch (state)
{
case 1:
System.Threading.Thread.Sleep(3000);
//some case code
break;
case 2:
System.Threading.Thread.Sleep(3000);
//some case code
break;
default:
System.Threading.Thread.Sleep(3000);
//some default code
break;
}
//rest of the code
}
Just to let You know, there should be other (and better) way to going through this, rather than using switch and this type of GOTO case this and this. Making the code unreadable in future.
Thread.Sleep(3000) you can use
I have extended a togglebutton control in Silverlight 5 and have created a Dependency property to Hold PathGeometry data. Expectedly the PathGeometry data is not being read. I'm not sure if its the converter or the setup. Here is all my code.
ExtentedRadTogglebutton.cs
public static readonly DependencyProperty ButtonIconPathDataProperty = DependencyProperty.Register(
"ButtonIconPathData",
typeof(PathGeometry),
typeof(ExtendedRadToggleButton),
new PropertyMetadata(new PathGeometry(), null));
Customised_RadToggleButtonControl.cs
if (!string.IsNullOrEmpty(settings.CusNav_L2_HomeButton_IconPathData))
{
StringToPathGeometryConverter cvSTGeo = new StringToPathGeometryConverter();
var iconPathData = cvSTGeo.Convert(settings.CusNav_L2_HomeButton_IconPathData,
null, null, null);
_radToggleButton.SetValue(ExtendedRadToggleButton.ButtonIconPathDataProperty, iconPathData);
}
XAML. resource
<Path x:Name="arrow"
Data="{TemplateBinding ButtonIconPathData}"/>
Converter
using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Globalization;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
namespace MyClub.SilverlightClient.Converter
{
public class StringToPathGeometryConverter : IValueConverter
{
#region Const & Private Variables
const bool AllowSign = true;
const bool AllowComma = true;
const bool IsFilled = true;
const bool IsClosed = true;
IFormatProvider _formatProvider;
PathFigure _figure = null; // Figure object, which will accept parsed segments
string _pathString; // Input string to be parsed
int _pathLength;
int _curIndex; // Location to read next character from
bool _figureStarted; // StartFigure is effective
Point _lastStart; // Last figure starting point
Point _lastPoint; // Last point
Point _secondLastPoint; // The point before last point
char _token; // Non whitespace character returned by ReadToken
#endregion
#region Public Functionality
/// <summary>
/// Main conversion routine - converts string path data definition to PathGeometry object
/// </summary>
/// <param name="path">String with path data definition</param>
/// <returns>PathGeometry object created from string definition</returns>
public PathGeometry Convert(string path)
{
if (null == path)
throw new ArgumentException("Path string cannot be null!");
if (path.Length == 0)
throw new ArgumentException("Path string cannot be empty!");
return parse(path);
}
/// <summary>
/// Main back conversion routine - converts PathGeometry object to its string equivalent
/// </summary>
/// <param name="geometry">Path Geometry object</param>
/// <returns>String equivalent to PathGeometry contents</returns>
public string ConvertBack(PathGeometry geometry)
{
if (null == geometry)
throw new ArgumentException("Path Geometry cannot be null!");
return parseBack(geometry);
}
#endregion
#region Private Functionality
/// <summary>
/// Main parser routine, which loops over each char in received string, and performs actions according to command/parameter being passed
/// </summary>
/// <param name="path">String with path data definition</param>
/// <returns>PathGeometry object created from string definition</returns>
private PathGeometry parse(string path)
{
PathGeometry _pathGeometry = null;
_formatProvider = CultureInfo.InvariantCulture;
_pathString = path;
_pathLength = path.Length;
_curIndex = 0;
_secondLastPoint = new Point(0, 0);
_lastPoint = new Point(0, 0);
_lastStart = new Point(0, 0);
_figureStarted = false;
bool first = true;
char last_cmd = ' ';
while (ReadToken()) // Empty path is allowed in XAML
{
char cmd = _token;
if (first)
{
if ((cmd != 'M') && (cmd != 'm') && (cmd != 'f') && (cmd != 'F')) // Path starts with M|m
{
ThrowBadToken();
}
first = false;
}
switch (cmd)
{
case 'f':
case 'F':
_pathGeometry = new PathGeometry();
double _num = ReadNumber(!AllowComma);
_pathGeometry.FillRule = _num == 0 ? FillRule.EvenOdd : FillRule.Nonzero;
break;
case 'm':
case 'M':
// XAML allows multiple points after M/m
_lastPoint = ReadPoint(cmd, !AllowComma);
_figure = new PathFigure();
_figure.StartPoint = _lastPoint;
_figure.IsFilled = IsFilled;
_figure.IsClosed = !IsClosed;
//context.BeginFigure(_lastPoint, IsFilled, !IsClosed);
_figureStarted = true;
_lastStart = _lastPoint;
last_cmd = 'M';
while (IsNumber(AllowComma))
{
_lastPoint = ReadPoint(cmd, !AllowComma);
LineSegment _lineSegment = new LineSegment();
_lineSegment.Point = _lastPoint;
_figure.Segments.Add(_lineSegment);
//context.LineTo(_lastPoint, IsStroked, !IsSmoothJoin);
last_cmd = 'L';
}
break;
case 'l':
case 'L':
case 'h':
case 'H':
case 'v':
case 'V':
EnsureFigure();
do
{
switch (cmd)
{
case 'l': _lastPoint = ReadPoint(cmd, !AllowComma); break;
case 'L': _lastPoint = ReadPoint(cmd, !AllowComma); break;
case 'h': _lastPoint.X += ReadNumber(!AllowComma); break;
case 'H': _lastPoint.X = ReadNumber(!AllowComma); break;
case 'v': _lastPoint.Y += ReadNumber(!AllowComma); break;
case 'V': _lastPoint.Y = ReadNumber(!AllowComma); break;
}
LineSegment _lineSegment = new LineSegment();
_lineSegment.Point = _lastPoint;
_figure.Segments.Add(_lineSegment);
//context.LineTo(_lastPoint, IsStroked, !IsSmoothJoin);
}
while (IsNumber(AllowComma));
last_cmd = 'L';
break;
case 'c':
case 'C': // cubic Bezier
case 's':
case 'S': // smooth cublic Bezier
EnsureFigure();
do
{
Point p;
if ((cmd == 's') || (cmd == 'S'))
{
if (last_cmd == 'C')
{
p = Reflect();
}
else
{
p = _lastPoint;
}
_secondLastPoint = ReadPoint(cmd, !AllowComma);
}
else
{
p = ReadPoint(cmd, !AllowComma);
_secondLastPoint = ReadPoint(cmd, AllowComma);
}
_lastPoint = ReadPoint(cmd, AllowComma);
BezierSegment _bizierSegment = new BezierSegment();
_bizierSegment.Point1 = p;
_bizierSegment.Point2 = _secondLastPoint;
_bizierSegment.Point3 = _lastPoint;
_figure.Segments.Add(_bizierSegment);
//context.BezierTo(p, _secondLastPoint, _lastPoint, IsStroked, !IsSmoothJoin);
last_cmd = 'C';
}
while (IsNumber(AllowComma));
break;
case 'q':
case 'Q': // quadratic Bezier
case 't':
case 'T': // smooth quadratic Bezier
EnsureFigure();
do
{
if ((cmd == 't') || (cmd == 'T'))
{
if (last_cmd == 'Q')
{
_secondLastPoint = Reflect();
}
else
{
_secondLastPoint = _lastPoint;
}
_lastPoint = ReadPoint(cmd, !AllowComma);
}
else
{
_secondLastPoint = ReadPoint(cmd, !AllowComma);
_lastPoint = ReadPoint(cmd, AllowComma);
}
QuadraticBezierSegment _quadraticBezierSegment = new QuadraticBezierSegment();
_quadraticBezierSegment.Point1 = _secondLastPoint;
_quadraticBezierSegment.Point2 = _lastPoint;
_figure.Segments.Add(_quadraticBezierSegment);
//context.QuadraticBezierTo(_secondLastPoint, _lastPoint, IsStroked, !IsSmoothJoin);
last_cmd = 'Q';
}
while (IsNumber(AllowComma));
break;
case 'a':
case 'A':
EnsureFigure();
do
{
// A 3,4 5, 0, 0, 6,7
double w = ReadNumber(!AllowComma);
double h = ReadNumber(AllowComma);
double rotation = ReadNumber(AllowComma);
bool large = ReadBool();
bool sweep = ReadBool();
_lastPoint = ReadPoint(cmd, AllowComma);
ArcSegment _arcSegment = new ArcSegment();
_arcSegment.Point = _lastPoint;
_arcSegment.Size = new Size(w, h);
_arcSegment.RotationAngle = rotation;
_arcSegment.IsLargeArc = large;
_arcSegment.SweepDirection = sweep ? SweepDirection.Clockwise : SweepDirection.Counterclockwise;
_figure.Segments.Add(_arcSegment);
//context.ArcTo(
// _lastPoint,
// new Size(w, h),
// rotation,
// large,
// sweep ? SweepDirection.Clockwise : SweepDirection.Counterclockwise,
// IsStroked,
// !IsSmoothJoin
// );
}
while (IsNumber(AllowComma));
last_cmd = 'A';
break;
case 'z':
case 'Z':
EnsureFigure();
_figure.IsClosed = IsClosed;
//context.SetClosedState(IsClosed);
_figureStarted = false;
last_cmd = 'Z';
_lastPoint = _lastStart; // Set reference point to be first point of current figure
break;
default:
ThrowBadToken();
break;
}
if (null != _figure)
{
if (_figure.IsClosed)
{
if (null == _pathGeometry)
_pathGeometry = new PathGeometry();
_pathGeometry.Figures.Add(_figure);
_figure = null;
first = true;
}
}
}
if (null != _figure)
{
if (null == _pathGeometry)
_pathGeometry = new PathGeometry();
if (!_pathGeometry.Figures.Contains(_figure))
_pathGeometry.Figures.Add(_figure);
}
return _pathGeometry;
}
void SkipDigits(bool signAllowed)
{
// Allow for a sign
if (signAllowed && More() && ((_pathString[_curIndex] == '-') || _pathString[_curIndex] == '+'))
{
_curIndex++;
}
while (More() && (_pathString[_curIndex] >= '0') && (_pathString[_curIndex] <= '9'))
{
_curIndex++;
}
}
bool ReadBool()
{
SkipWhiteSpace(AllowComma);
if (More())
{
_token = _pathString[_curIndex++];
if (_token == '0')
{
return false;
}
else if (_token == '1')
{
return true;
}
}
ThrowBadToken();
return false;
}
private Point Reflect()
{
return new Point(2 * _lastPoint.X - _secondLastPoint.X,
2 * _lastPoint.Y - _secondLastPoint.Y);
}
private void EnsureFigure()
{
if (!_figureStarted)
{
_figure = new PathFigure();
_figure.StartPoint = _lastStart;
//_context.BeginFigure(_lastStart, IsFilled, !IsClosed);
_figureStarted = true;
}
}
double ReadNumber(bool allowComma)
{
if (!IsNumber(allowComma))
{
ThrowBadToken();
}
bool simple = true;
int start = _curIndex;
//
// Allow for a sign
//
// There are numbers that cannot be preceded with a sign, for instance, -NaN, but it's
// fine to ignore that at this point, since the CLR parser will catch this later.
//
if (More() && ((_pathString[_curIndex] == '-') || _pathString[_curIndex] == '+'))
{
_curIndex++;
}
// Check for Infinity (or -Infinity).
if (More() && (_pathString[_curIndex] == 'I'))
{
//
// Don't bother reading the characters, as the CLR parser will
// do this for us later.
//
_curIndex = Math.Min(_curIndex + 8, _pathLength); // "Infinity" has 8 characters
simple = false;
}
// Check for NaN
else if (More() && (_pathString[_curIndex] == 'N'))
{
//
// Don't bother reading the characters, as the CLR parser will
// do this for us later.
//
_curIndex = Math.Min(_curIndex + 3, _pathLength); // "NaN" has 3 characters
simple = false;
}
else
{
SkipDigits(!AllowSign);
// Optional period, followed by more digits
if (More() && (_pathString[_curIndex] == '.'))
{
simple = false;
_curIndex++;
SkipDigits(!AllowSign);
}
// Exponent
if (More() && ((_pathString[_curIndex] == 'E') || (_pathString[_curIndex] == 'e')))
{
simple = false;
_curIndex++;
SkipDigits(AllowSign);
}
}
if (simple && (_curIndex <= (start + 8))) // 32-bit integer
{
int sign = 1;
if (_pathString[start] == '+')
{
start++;
}
else if (_pathString[start] == '-')
{
start++;
sign = -1;
}
int value = 0;
while (start < _curIndex)
{
value = value * 10 + (_pathString[start] - '0');
start++;
}
return value * sign;
}
else
{
string subString = _pathString.Substring(start, _curIndex - start);
try
{
return System.Convert.ToDouble(subString, _formatProvider);
}
catch (FormatException except)
{
throw new FormatException(string.Format("Unexpected character in path '{0}' at position {1}", _pathString, _curIndex - 1), except);
}
}
}
private bool IsNumber(bool allowComma)
{
bool commaMet = SkipWhiteSpace(allowComma);
if (More())
{
_token = _pathString[_curIndex];
// Valid start of a number
if ((_token == '.') || (_token == '-') || (_token == '+') || ((_token >= '0') && (_token <= '9'))
|| (_token == 'I') // Infinity
|| (_token == 'N')) // NaN
{
return true;
}
}
if (commaMet) // Only allowed between numbers
{
ThrowBadToken();
}
return false;
}
private Point ReadPoint(char cmd, bool allowcomma)
{
double x = ReadNumber(allowcomma);
double y = ReadNumber(AllowComma);
if (cmd >= 'a') // 'A' < 'a'. lower case for relative
{
x += _lastPoint.X;
y += _lastPoint.Y;
}
return new Point(x, y);
}
private bool ReadToken()
{
SkipWhiteSpace(!AllowComma);
// Check for end of string
if (More())
{
_token = _pathString[_curIndex++];
return true;
}
else
{
return false;
}
}
bool More()
{
return _curIndex < _pathLength;
}
// Skip white space, one comma if allowed
private bool SkipWhiteSpace(bool allowComma)
{
bool commaMet = false;
while (More())
{
char ch = _pathString[_curIndex];
switch (ch)
{
case ' ':
case '\n':
case '\r':
case '\t': // SVG whitespace
break;
case ',':
if (allowComma)
{
commaMet = true;
allowComma = false; // one comma only
}
else
{
ThrowBadToken();
}
break;
default:
// Avoid calling IsWhiteSpace for ch in (' ' .. 'z']
if (((ch > ' ') && (ch <= 'z')) || !Char.IsWhiteSpace(ch))
{
return commaMet;
}
break;
}
_curIndex++;
}
return commaMet;
}
private void ThrowBadToken()
{
throw new FormatException(string.Format("Unexpected character in path '{0}' at position {1}", _pathString, _curIndex - 1));
}
static internal char GetNumericListSeparator(IFormatProvider provider)
{
char numericSeparator = ',';
// Get the NumberFormatInfo out of the provider, if possible
// If the IFormatProvider doesn't not contain a NumberFormatInfo, then
// this method returns the current culture's NumberFormatInfo.
NumberFormatInfo numberFormat = NumberFormatInfo.GetInstance(provider);
// Is the decimal separator is the same as the list separator?
// If so, we use the ";".
if ((numberFormat.NumberDecimalSeparator.Length > 0) && (numericSeparator == numberFormat.NumberDecimalSeparator[0]))
{
numericSeparator = ';';
}
return numericSeparator;
}
private string parseBack(PathGeometry geometry)
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
IFormatProvider provider = new System.Globalization.CultureInfo("en-us");
string format = null;
sb.Append("F" + (geometry.FillRule == FillRule.EvenOdd ? "0" : "1") + " ");
foreach (PathFigure figure in geometry.Figures)
{
sb.Append("M " + ((IFormattable)figure.StartPoint).ToString(format, provider) + " ");
foreach (PathSegment segment in figure.Segments)
{
char separator = GetNumericListSeparator(provider);
if (segment.GetType() == typeof(LineSegment))
{
LineSegment _lineSegment = segment as LineSegment;
sb.Append("L " + ((IFormattable)_lineSegment.Point).ToString(format, provider) + " ");
}
else if (segment.GetType() == typeof(BezierSegment))
{
BezierSegment _bezierSegment = segment as BezierSegment;
sb.Append(String.Format(provider,
"C{1:" + format + "}{0}{2:" + format + "}{0}{3:" + format + "} ",
separator,
_bezierSegment.Point1,
_bezierSegment.Point2,
_bezierSegment.Point3
));
}
else if (segment.GetType() == typeof(QuadraticBezierSegment))
{
QuadraticBezierSegment _quadraticBezierSegment = segment as QuadraticBezierSegment;
sb.Append(String.Format(provider,
"Q{1:" + format + "}{0}{2:" + format + "} ",
separator,
_quadraticBezierSegment.Point1,
_quadraticBezierSegment.Point2));
}
else if (segment.GetType() == typeof(ArcSegment))
{
ArcSegment _arcSegment = segment as ArcSegment;
sb.Append(String.Format(provider,
"A{1:" + format + "}{0}{2:" + format + "}{0}{3}{0}{4}{0}{5:" + format + "} ",
separator,
_arcSegment.Size,
_arcSegment.RotationAngle,
_arcSegment.IsLargeArc ? "1" : "0",
_arcSegment.SweepDirection == SweepDirection.Clockwise ? "1" : "0",
_arcSegment.Point));
}
}
if (figure.IsClosed)
sb.Append("Z");
}
return sb.ToString();
}
#endregion
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
string path = value as string;
if (null != path)
return Convert(path);
else
return null;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
PathGeometry geometry = value as PathGeometry;
if (null != geometry)
return ConvertBack(geometry);
else
return default(string);
}
#endregion
}
}
I have a program that generates C# from bits of C# stored in an XML file. If I have a snippet like:
foo {bar}
I need to transform that into an interpolated string, like this:
$#"foo {bar}"
The problem is that, if I have quotes outside a placeholder, e.g.:
"foo" {bar}
I need to double those:
$#"""foo"" {bar}"
but ignore quotes inside placeholders:
foo {"bar"}
should produce:
$#"foo {"bar"}"
Also, need to look out for doubled braces:
foo {{"bar"}}
should produce:
$#"foo {{""bar""}}"
And perhaps the trickiest of all, if the placeholder is preceded and/or followed by an even number of braces:
foo {{{"bar"}}}
should produce:
$#"foo {{{"bar"}}}"
In short, if there's a placeholder then ignore everything inside. For the rest of the text, double quotes.
Can this be accomplished using regular expressions? If not, what alternatives do I have?
You will need at least 2 steps:
Add quotes inside the expression:
"(?=[^}]*(?:}})*[^}]*$)|(?<=^[^{]*(?:{{)*)" =>
replace with ""
See demo
Enclose in $#"..." with string.Format("$#\"{0}\"", str);
Here is an IDEONE demo
var s = "\"foo\" {bar}";
var rx = new Regex(#"(?<!(?<!{){[^{}]*)""(?![^{}]*}(?!}))");
Console.WriteLine(string.Format("$#\"{0}\"",rx.Replace(s,"\"\"")));
And another demo here
This cannot be done with regular expressions. Knowing when a placeholder starts is easy, knowing when it ends is the hard part, since a placeholder can hold almost any C# expression, so you have to keep track of blocks ({}) and literals (strings, chars, comments) because any brace in a literal is not significant.
This is the code I came up with:
enum ParsingMode {
Text,
Code,
InterpolatedString,
InterpolatedVerbatimString,
String,
VerbatimString,
Char,
MultilineComment
}
public static string EscapeValueTemplate(string valueTemplate) {
if (valueTemplate == null) throw new ArgumentNullException(nameof(valueTemplate));
var quoteIndexes = new List<int>();
var modeStack = new Stack<ParsingMode>();
modeStack.Push(ParsingMode.Text);
Func<ParsingMode> currentMode = () => modeStack.Peek();
for (int i = 0; i < valueTemplate.Length; i++) {
char c = valueTemplate[i];
Func<char?> nextChar = () =>
i + 1 < valueTemplate.Length ? valueTemplate[i + 1]
: default(char?);
switch (currentMode()) {
case ParsingMode.Code:
switch (c) {
case '{':
modeStack.Push(ParsingMode.Code);
break;
case '}':
modeStack.Pop();
break;
case '\'':
modeStack.Push(ParsingMode.Char);
break;
case '"':
ParsingMode stringMode = ParsingMode.String;
switch (valueTemplate[i - 1]) {
case '#':
if (i - 2 >= 0 && valueTemplate[i - 2] == '$') {
stringMode = ParsingMode.InterpolatedVerbatimString;
} else {
stringMode = ParsingMode.VerbatimString;
}
break;
case '$':
stringMode = ParsingMode.InterpolatedString;
break;
}
modeStack.Push(stringMode);
break;
case '/':
if (nextChar() == '*') {
modeStack.Push(ParsingMode.MultilineComment);
i++;
}
break;
}
break;
case ParsingMode.Text:
case ParsingMode.InterpolatedString:
case ParsingMode.InterpolatedVerbatimString:
switch (c) {
case '{':
if (nextChar() == '{') {
i++;
} else {
modeStack.Push(ParsingMode.Code);
}
break;
case '"':
switch (currentMode()) {
case ParsingMode.Text:
quoteIndexes.Add(i);
break;
case ParsingMode.InterpolatedString:
modeStack.Pop();
break;
case ParsingMode.InterpolatedVerbatimString:
if (nextChar() == '"') {
i++;
} else {
modeStack.Pop();
}
break;
}
break;
case '\\':
if (currentMode() == ParsingMode.InterpolatedString) {
i++;
}
break;
}
break;
case ParsingMode.String:
switch (c) {
case '\\':
i++;
break;
case '"':
modeStack.Pop();
break;
}
break;
case ParsingMode.VerbatimString:
if (c == '"') {
if (nextChar() == '"') {
i++;
} else {
modeStack.Pop();
}
}
break;
case ParsingMode.Char:
switch (c) {
case '\\':
i++;
break;
case '\'':
modeStack.Pop();
break;
}
break;
case ParsingMode.MultilineComment:
if (c == '*') {
if (nextChar() == '/') {
modeStack.Pop();
i++;
}
}
break;
}
}
var sb = new StringBuilder(valueTemplate, valueTemplate.Length + quoteIndexes.Count);
for (int i = 0; i < quoteIndexes.Count; i++) {
sb.Insert(quoteIndexes[i] + i, '"');
}
return sb.ToString();
}
I am working on a logic that decreases the value of an alphanumeric List<char>. For example, A10 becomes A9, BBA becomes BAZ, 123 becomes 122. And yes, if the value entered is the last one(like A or 0), then I should return -
An additional overhead is that there is a List<char> variable which is maintained by the user. It has characters which are to be skipped. For example, if the list contains A in it, the value GHB should become GGZ and not GHA.
The base of this logic is a very simple usage of decreasing the char but with these conditions, I am finding it very difficult.
My project is in Silverlight, the language is C#. Following is my code that I have been trying to do in the 3 methods:
List<char> lstGetDecrName(List<char> lstVal)//entry point of the value that returns decreased value
{
List<char> lstTmp = lstVal;
subCheckEmpty(ref lstTmp);
switch (lstTmp.Count)
{
case 0:
lstTmp.Add('-');
return lstTmp;
case 1:
if (lstTmp[0] == '-')
{
return lstTmp;
}
break;
case 2:
if (lstTmp[1] == '0')
{
if (lstTmp[0] == '1')
{
lstTmp.Clear();
lstTmp.Add('9');
return lstTmp;
}
if (lstTmp[0] == 'A')
{
lstTmp.Clear();
lstTmp.Add('-');
return lstTmp;
}
}
if (lstTmp[1] == 'A')
{
if (lstTmp[0] == 'A')
{
lstTmp.Clear();
lstTmp.Add('Z');
return lstTmp;
}
}
break;
}
return lstGetDecrValue(lstTmp,lstVal);
}
List<char> lstGetDecrValue(List<char> lstTmp,List<char> lstVal)
{
List<char> lstValue = new List<char>();
switch (lstTmp.Last())
{
case 'A':
lstValue = lstGetDecrTemp('Z', lstTmp, lstVal);
break;
case 'a':
lstValue = lstGetDecrTemp('z', lstTmp, lstVal);
break;
case '0':
lstValue = lstGetDecrTemp('9', lstTmp, lstVal);
break;
default:
char tmp = (char)(lstTmp.Last() - 1);
lstTmp.RemoveAt(lstTmp.Count - 1);
lstTmp.Add(tmp);
lstValue = lstTmp;
break;
}
return lstValue;
}
List<char> lstGetDecrTemp(char chrTemp, List<char> lstTmp, List<char> lstVal)//shifting places eg unit to ten,etc.
{
if (lstTmp.Count == 1)
{
lstTmp.Clear();
lstTmp.Add('-');
return lstTmp;
}
lstTmp.RemoveAt(lstTmp.Count - 1);
lstVal = lstGetDecrName(lstTmp);
lstVal.Insert(lstVal.Count, chrTemp);
return lstVal;
}
I seriously need help for this. Please help me out crack through this.
The problem you are trying to solve is actually how to decrement discreet sections of a sequence of characters, each with it's own counting system, where each section is separated by a change between Alpha and Numeric. The rest of the problem is easy once you identify this.
The skipping of unwanted characters is simply a matter of repeating the decrement if you get an unwanted character in the result.
One difficultly is the ambiguous definition of the sequences. e.g. what to do when you get down to say A00, what is next? "A" or "-". For the sake of argument I am assuming a practical implementation based loosely on Excel cell names (i.e. each section operates independently of the others).
The code below does 95% of what you wanted, however there is a bug in the exclusions code. e.g. "ABB" becomes "AAY". I feel the exclusions need to be applied at a higher level (e.g. repeat decrement until no character is in the exclusions list), but I don't have time to finish it now. Also it is resulting in a blank string when it counts down to nothing, rather than the "-" you wanted, but that is trivial to add at the end of the process.
Part 1 (divide the problem into sections):
public static string DecreaseName( string name, string exclusions )
{
if (string.IsNullOrEmpty(name))
{
return name;
}
// Split the problem into sections (reverse order)
List<StringBuilder> sections = new List<StringBuilder>();
StringBuilder result = new StringBuilder(name.Length);
bool isNumeric = char.IsNumber(name[0]);
StringBuilder sb = new StringBuilder();
sections.Add(sb);
foreach (char c in name)
{
// If we change between alpha and number, start new string.
if (char.IsNumber(c) != isNumeric)
{
isNumeric = char.IsNumber(c);
sb = new StringBuilder();
sections.Insert(0, sb);
}
sb.Append(c);
}
// Now process each section
bool cascadeToNext = true;
foreach (StringBuilder section in sections)
{
if (cascadeToNext)
{
result.Insert(0, DecrementString(section, exclusions, out cascadeToNext));
}
else
{
result.Insert(0, section);
}
}
return result.ToString().Replace(" ", "");
}
Part2 (decrement a given string):
private static string DecrementString(StringBuilder section, string exclusions, out bool cascadeToNext)
{
bool exclusionsExist = false;
do
{
exclusionsExist = false;
cascadeToNext = true;
// Process characters in reverse
for (int i = section.Length - 1; i >= 0 && cascadeToNext; i--)
{
char c = section[i];
switch (c)
{
case 'A':
c = (i > 0) ? 'Z' : ' ';
cascadeToNext = (i > 0);
break;
case 'a':
c = (i > 0) ? 'z' : ' ';
cascadeToNext = (i > 0);
break;
case '0':
c = (i > 0) ? '9' : ' ';
cascadeToNext = (i > 0);
break;
case ' ':
cascadeToNext = false;
break;
default:
c = (char)(((int)c) - 1);
if (i == 0 && c == '0')
{
c = ' ';
}
cascadeToNext = false;
break;
}
section[i] = c;
if (exclusions.Contains(c.ToString()))
{
exclusionsExist = true;
}
}
} while (exclusionsExist);
return section.ToString();
}
The dividing can of course be done more efficiently, just passing start and end indexes to the DecrementString, but this is easier to write & follow and not much slower in practical terms.
do a check if its a number if so then do a minus math of the number, if its a string then change it to char codes and then the char code minus 1
I couldn't stop thinking about this yesterday, so here's an idea. Note, this is just pseudo-code, and not tested, but I think the idea is valid and should work (with a few modifications).
The main point is to define your "alphabet" directly, and specify which characters in it are illegal and should be skipped, then use a list or array of positions in this alphabet to define the word you start with.
I can't spend any more time on this right now, but please let me know if you decide to use it and get it to work!
string[] alphabet = {a, b, c, d, e};
string[] illegal = {c, d};
public string ReduceString(string s){
// Create a list of the alphabet-positions for each letter:
int[] positionList = s.getCharsAsPosNrsInAlphabet();
int[] reducedPositionList = ReduceChar(positionList, positionList.length);
string result = "";
foreach(int pos in reducedPositionList){
result += alphabet[pos];
}
return result;
}
public string ReduceChar(string[] positionList, posToReduce){
int reducedCharPosition = ReduceToNextLegalChar(positionList[posToReduce]);
// put reduced char back in place:
positionList[posToReduce] = reducedCharPosition;
if(reducedCharPosition < 0){
if(posToReduce <= 0){
// Reached the end, reduced everything, return empty array!:
return new string[]();
}
// move to back of alphabet again (ie, like the 9 in "11 - 2 = 09"):
reducedCharPosition += alphabet.length;
// Recur and reduce next position (ie, like the 0 in "11 - 2 = 09"):
return ReduceChar(positionList, posToReduce-1);
}
return positionList;
}
public int ReduceToNextLegalChar(int pos){
int nextPos = pos--;
return (isLegalChar(nextPos) ? nextPos : ReduceToNextLegalChar(nextPos));
}
public boolean IsLegalChar(int pos){
return (! illegal.contains(alphabet[pos]));
}
enter code here
Without writing all your code for you, here's a suggestion as to how you can break this down:
char DecrementAlphaNumericChar(char input, out bool hadToWrap)
{
if (input == 'A')
{
hadToWrap = true;
return 'Z';
}
else if (input == '0')
{
hadToWrap = true;
return '9';
}
else if ((input > 'A' && input <= 'Z') || (input > '0' && input <= '9'))
{
hadToWrap = false;
return (char)((int)input - 1);
}
throw new ArgumentException(
"Characters must be digits or capital letters",
"input");
}
char DecrementAvoidingProhibited(
char input, List<char> prohibited, out bool hadToWrap)
{
var potential = DecrementAlphaNumericChar(input, out hadToWrap);
while (prohibited.Contains(potential))
{
bool temp;
potential = DecrementAlphaNumericChar(potential, out temp);
if (potential == input)
{
throw new ArgumentException(
"A whole class of characters was prohibited",
"prohibited");
}
hadToWrap |= temp;
}
return potential;
}
string DecrementString(string input, List<char> prohibited)
{
char[] chrs = input.ToCharArray();
for (int i = chrs.Length - 1; i >= 0; i--)
{
bool wrapped;
chrs[i] = DecrementAvoidingProhibited(
chrs[i], prohibited, out wrapped);
if (!wrapped)
return new string(chrs);
}
return "-";
}
The only issue here is that it will reduce e.g. A10 to A09 not A9. I actually prefer this myself, but it should be simple to write a final pass that removes the extra zeroes.
For a little more performance, replace the List<char>s with Hashset<char>s, they should allow a faster Contains lookup.
I found solution to my own answer with some other workarounds.
The calling function:
MyFunction()
{
//stuff I do before
strValue = lstGetDecrName(strValue.ToList());//decrease value here
if (strValue.Contains('-'))
{
strValue = "-";
}
//stuff I do after
}
In all there are 4 functions. 2 Main functions and 2 helper functions.
List<char> lstGetDecrName(List<char> lstVal)//entry point, returns decreased value
{
if (lstVal.Contains('-'))
{
return "-".ToList();
}
List<char> lstTmp = lstVal;
subCheckEmpty(ref lstTmp);
switch (lstTmp.Count)
{
case 0:
lstTmp.Add('-');
return lstTmp;
case 1:
if (lstTmp[0] == '-')
{
return lstTmp;
}
break;
case 2:
if (lstTmp[1] == '0')
{
if (lstTmp[0] == '1')
{
lstTmp.Clear();
lstTmp.Add('9');
return lstTmp;
}
if (lstTmp[0] == 'A')
{
lstTmp.Clear();
lstTmp.Add('-');
return lstTmp;
}
}
if (lstTmp[1] == 'A')
{
if (lstTmp[0] == 'A')
{
lstTmp.Clear();
lstTmp.Add('Z');
return lstTmp;
}
}
break;
}
List<char> lstValue = new List<char>();
switch (lstTmp.Last())
{
case 'A':
lstValue = lstGetDecrTemp('Z', lstTmp, lstVal);
break;
case 'a':
lstValue = lstGetDecrTemp('z', lstTmp, lstVal);
break;
case '0':
lstValue = lstGetDecrTemp('9', lstTmp, lstVal);
break;
default:
char tmp = (char)(lstTmp.Last() - 1);
lstTmp.RemoveAt(lstTmp.Count - 1);
lstTmp.Add(tmp);
subCheckEmpty(ref lstTmp);
lstValue = lstTmp;
break;
}
lstGetDecrSkipValue(lstValue);
return lstValue;
}
List<char> lstGetDecrSkipValue(List<char> lstValue)
{
bool blnSkip = false;
foreach (char tmpChar in lstValue)
{
if (lstChars.Contains(tmpChar))
{
blnSkip = true;
break;
}
}
if (blnSkip)
{
lstValue = lstGetDecrName(lstValue);
}
return lstValue;
}
void subCheckEmpty(ref List<char> lstTmp)
{
bool blnFirst = true;
int i = -1;
foreach (char tmpChar in lstTmp)
{
if (char.IsDigit(tmpChar) && blnFirst)
{
i = tmpChar == '0' ? lstTmp.IndexOf(tmpChar) : -1;
if (tmpChar == '0')
{
i = lstTmp.IndexOf(tmpChar);
}
blnFirst = false;
}
}
if (!blnFirst && i != -1)
{
lstTmp.RemoveAt(i);
subCheckEmpty(ref lstTmp);
}
}
List<char> lstGetDecrTemp(char chrTemp, List<char> lstTmp, List<char> lstVal)//shifting places eg unit to ten,etc.
{
if (lstTmp.Count == 1)
{
lstTmp.Clear();
lstTmp.Add('-');
return lstTmp;
}
lstTmp.RemoveAt(lstTmp.Count - 1);
lstVal = lstGetDecrName(lstTmp);
lstVal.Insert(lstVal.Count, chrTemp);
subCheckEmpty(ref lstVal);
return lstVal;
}
I have a textbox using UseSystemPasswordChar, so it will not display the password that the user enters. The issue is that the password is still able to be read by something like Spy++. I'm looking for a way to hide this like they do in the password fields in the Services.msc > Log On tab.
Here is what I've got so far.
You can improve this by having some unique events to indicate whether a pressed key has been accepted, if InputFilter or RealText has been changed, etc...
Another great thing to improve would be the default usage of InputFilter, because working with char and Keys doesn't really work for many special keys. For example - at the moment, if you press Alt+F4 when the PasswordBox is in focus, it will type in 's'... So there's a bag of bugs to fix.
And lastly, there's probably a more elegant way to handle capital vs non-capital letters input than what I did there.
So here it is:
public class PasswordBox : TextBox
{
private string _realText;
public string RealText
{
get { return this._realText; }
set
{
var i = this.SelectionStart;
this._realText = value ?? "";
this.Text = "";
this.Text = new string('*', this._realText.Length);
this.SelectionStart = i > this.Text.Length ? this.Text.Length : i;
}
}
private Func<KeyEventArgs, bool> _inputFilter;
public Func<KeyEventArgs, bool> InputFilter
{
get { return this._inputFilter; }
set { this._inputFilter = value ?? (e => true); }
}
public PasswordBox()
{
this.RealText = "";
this.InputFilter = e => "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".Any(c => c == e.KeyValue);
}
protected override void OnKeyDown(KeyEventArgs e)
{
e.SuppressKeyPress = true;
switch (e.KeyCode)
{
case Keys.Back:
if (this.SelectionStart > 0 || this.SelectionLength > 0)
{
this.RealText = this.SelectionLength == 0
? this.RealText.Remove(--this.SelectionStart, 1)
: this.RealText.Remove(this.SelectionStart, this.SelectionLength);
}
break;
case Keys.Delete:
if (this.SelectionStart == this.TextLength)
{
return;
}
this.RealText = this.RealText.Remove(this.SelectionStart, this.SelectionLength == 0 ? 1 : this.SelectionLength);
break;
case Keys.X:
case Keys.C:
case Keys.V:
if (e.Control)
{
return;
}
goto default;
case Keys.Right:
case Keys.Left:
case Keys.Up:
case Keys.Down:
case Keys.Shift:
case Keys.Home:
case Keys.End:
e.SuppressKeyPress = false;
base.OnKeyDown(e);
break;
default:
if (e.Control)
{
e.SuppressKeyPress = false;
base.OnKeyDown(e);
break;
}
if (this.InputFilter(e))
{
var c = (char)e.KeyValue;
if (e.Shift == IsKeyLocked(Keys.CapsLock))
{
c = char.ToLower(c);
}
this.RealText = this.RealText.Remove(this.SelectionStart, this.SelectionLength)
.Insert(this.SelectionStart, c.ToString());
this.SelectionStart++;
}
break;
}
}
}
So try something like this
private string realpass = "";
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (Char) Keys.Back)
realpass += realpass.Substring(0, realpass.Length - 2);
realpass += e.KeyChar.ToString();
textBox1.Text = "";
for (int i = 0; i < realpass.Length; i++)
textBox1.Text += "*";
}
You should not use your own dialog if you intend to collect Windows/domain user credentials. You should use what Windows provides via PInvoke or simply use a wrapper like this,
http://weblogs.asp.net/hernandl/archive/2005/11/21/usercredentialsdialog.aspx
and this,
http://credentials.codeplex.com/