I'm trying to work my way through Ron Jeffries's Extreme Programming Adventures in C#. I am stuck, however, in Chapter 3 because the code does not, and cannot, do what the author says it does.
Basically, the text says that I should be able to write some text in a word-wrap enabled text box. If I then move the cursor to an intermediate line and hit enter, the code should re-display the lines before the cursor, add a couple of lines and a set of HTML paragraph tags, then append the rest of the lines. The code doesn't match the text because it uses the textbox.lines property. Well, no matter how many word-wrapped lines there are in a text box, there's only ONE line in the Lines property until you hit a carriage return. So, the statement that the code should, "Copy the rest of the lines into the buffer" appears wrong to me.
I'd appreciate anybody having experience with the book telling me what I'm reading, or doing, wrong!
Thanks.
EoRaptor
Try emailing Ron Jeffries directly. I have the book - somewhere, but I don't remember it not working. His email address is ronjeffries at acm dot org and put [Ron] in the subject line.
(And for those wondering - his email info was right from his website Welcome page)
I've also just started this book and had exactly the same problem although the code you have included looks further along than where I am.
The 'subscript out of range' occurred for 2 reasons, first as Ron explains he was just testing and so returned a hard-coded value of 3 before he wrote the CursorLine() function, which means you I think at least 4? lines of text which as you say need to be pasted in, or maybe set the text to this value before running, also as you say they need to have carriage returns to make txtbox.Lines return an array of strings.
The second reason occurs even after CursorLine() has been implemented but only happens if the text box is empty as txtbox.Lines returns string[0] but I think Ron is implementing a 'User Story' which says that when text has been entered and user presses enter, so not sure if he fixes this later, but will probably find out!
The author's do state that they are learning C# and will show the development wart's and all, which is one of the reasons I have chosen to study this book as I think it is encouraging me to develop projects. I also try to do the code first before looking at his solutions to see if I'm thinking the same way, but maybe I know C# a little better than I give myself credit for, or I'm completly crap, but I've noticed a few things, first he says that overriding OnKeyDown() doesn't work, but I think he must have got confused and tried to do in Form, instead of deriving from TextBox and overriding there.
This was my code when reading the 'User Story':
int curPos = txtbox.SelectionStart;
string Wrd = Environment.NewLine + "<P></P>" + Environment.NewLine;
txtbox.SelectedText = Wrd;
int pl = Environment.NewLine.Length + 3; // "<P>" length is 3
// Put text cursor inbetween <P> tags
txtbox.SelectionStart = curPos + pl;
It works differently to Ron's code, but was just my interpretation of the 'User Story' and not sure how should act if text is selected or wether to split line if text cursor in the middle etc.
Also in 'My Adventures' in Extreme Programming Adventures in C#
txtbox.GetLineFromCharIndex(txtbox.SelectionStart)
gets the cursor line position and doesn't matter if no carriage returns or resized,
as far as I can tell, I done little test with:
txtbox.GetLineFromCharIndex(txtbox.TextLength)
which returns the total amount of lines, which will vary if you resize the text box.
Using C# I always look for solutions which already exsist and people may slate me for this but I think MS have created a great language with great components which do what you expect them to do, so don't have to re-create the wheel each time.
Although like I say it's early days in this book and perhaps these simple solutions aren't extensible enough and maybe Ron's taking that into account, although he did mention just get it working then worry about that later is more the XP way.
Warren.
print("using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
namespace NotepadOne {
public class TextModel {
private String[] lines;
private int selectionStart;
private int cursorPosition;
public TextModel() {
}
public String[] Lines {
get {
return lines;
}
set {
lines = value;
}
}
public int SelectionStart {
get {
return selectionStart;
}
set {
selectionStart = value;
}
}
public int CursorPosition {
get {
return cursorPosition;
}
set {
cursorPosition = value;
}
}
public void InsertControlPText() {
lines[lines.Length - 1] += "ControlP";
}
public void InsertParagraphTags() {
int cursorLine = CursorLine();
String[] newlines = new String[lines.Length + 2];
for (int i = 0; i <= cursorLine; i++) {
newlines[i] = lines[i];
}
newlines[cursorLine + 1] = "";
newlines[cursorLine + 2] = "<P></P>";
for (int i = cursorLine + 1; i < lines.Length; i++) {
newlines[i + 2] = lines[i];
}
lines = newlines;
selectionStart = NewSelectionStart(cursorLine + 2);
}
private int CursorLine() {
int length = 0;
int lineNr = 0;
foreach (String s in lines) {
if (length <= SelectionStart && SelectionStart <= length + s.Length + 2) {
break;
length += s.Length + Environment.NewLine.Length;
lineNr++;
}
lineNr++;
}
return lineNr;
}
private int NewSelectionStart(int cursorLine) {
int length = 0;
for (int i = 0; i < cursorLine; i++) {
length += lines[i].Length + Environment.NewLine.Length;
}
return length + 3;
}
}
}
");
The InsertParagraphTags method is called by pressing the enter key in the textbox.
BTW, the break here is that there is a subscript out of range error if you try to hit enter at the end of the text. I'm sure I could figure out how to get around this but then my code won't look like his code; which is what I'm trying to learn.
Randy
Related
I've been working on a project where I need on a button press that this line gets executed.
if (listView1.SelectedItems[0].SubItems[3].Text == "0") //Checks to see Value
{
listView1.SelectedItems[0].SubItems[3].Text = "1";// If Value is Greater, Increase and Change ListView
questionNumberLabel.Text = listView1.SelectedItems[0].SubItems[3].Text;// Increase and Change Label
}
Now I have this repeated about 10 times with each value increasing by one. But I know that this is ugly, and dysfunctional. As well as conflates the file size. I've tried a few things. Primarily this method.
if (listView1.SelectedItems[0].SubItems[3].Text == "0")
{
for (var i = 1; i < 100;)
{
if (!Int32.TryParse(listView1.SelectedItems[0].SubItems[3].Text, out i))
{
i = 0;
}
i++;
listView1.SelectedItems[0].SubItems[3].Text = i.ToString();
Console.WriteLine(i);
}
}
But instead of just adding one, it does the 100 instances and ends. The reason this is becoming a pain in the *** is because the
listView1.SelectedItems[0].SubItems[3].Text
is just that - it's a string, not an int. That's why I parsed it and tried to run it like that. But it still isn't having the out come I want.
I've also tried this
string listViewItemToChange = listView1.SelectedItems[0].SubItems[3].Text;
Then parsing the string, to make it prettier. It worked like it did before, but still hasn't given me the outcome I want. Which to reiterate is, I'm wanting the String taken from the list view to be changed into an int, used in the for loop, add 1, then restring it and output it on my listView.
Please help :(
You say you want the text from a listview subitem converted to an int which is then used in a loop
so - first your creating your loop variable, i, then in your loop you're assigning to it potentially 3 different values 2 of which are negated by the, i++. None of it makes sense and you shouldn't be manipulating your loop variable like that (unless understand what you're doing).
if you move statements around a little..
int itemsToCheck = 10; // "Now I have this repeated about 10 times "
for (var item = 0; item < itemsToCheck; item++)
{
int i;
if (!Int32.TryParse(listView1.SelectedItems[item].SubItems[3].Text, out i))
{
i = 0;
}
i++;
listView1.SelectedItems[item].SubItems[3].Text = i.ToString();
Console.WriteLine(i);
}
Something along those lines is what you're looking for. I haven't changed what your code does with i, just added a loop count itemsToCheck and used a different loop variable so your loop variable and parsed value are not one in the same which will likely be buggy.
Maybe this give you an idea. You can start using this syntax from C# 7.0
var s = listView1.SelectedItems[0].SubItems[3].Text;
var isNumeric = int.TryParse(s, out int n);
if(isNumeric is true && n > 0){
questionNumberLabel.Text = s;
}
to shortcut more
var s = listView1.SelectedItems[0].SubItems[3].Text;
if(int.TryParse(s, out int n) && n > 0){
questionNumberLabel.Text = s;
}
I have this line in my code-behind:
lblAboutMe.Text = (DT1["UserBody"].ToString());
No problems. But now, we want to only show the beginning of the paragraph and then an ellipsis. So, instead of being:
Please read it all as I hate wasting time with people that don't. If
you have an issue with Muslim's please move on as I do not. I used to
practice Islam and while I no longer do I still respect it and hate
the ignorance people show by following the media or stigma instead of
experiencing it or talking with Muslim's to educate themselves about
it. Referring to the no drug policy later in this profile, yes,
pot/marijuana counts as a drug and is a no with me so please move on.
I know what follows makes me seem cold but I am really quite warm and
loving, very devoted to the right one, i am just tired of being played
and taken for granted/ advantage of. People lie soooo much and ignore
so much of what I say I do not want. I have been told many times on
here that what I seek is too much.
We want to take just the first, say, 100 characters and follow it with an ellipsis. So, something like:
Please read it all as I hate wasting time with people that don't. If
you have an issue with Muslim's please move on as I do not. I used to
practice Islam and while I no longer do I still respect it and hate
the ignorance people show by following the media or stigma instead of
experiencing it or talking with Muslim's to educate themselves ...
How can we do this in code-behind? I have a feeling it's pretty easy (because it would be easy in Access), but I'm still new to this language.
Use Length to determine your string length, then use Substring to take some of it (100 chars) if it is too long:
string aboutme = DT1["UserBody"] != null ? DT1["UserBody"].ToString() : ""; //just in case DT1["UserBody"] is null
lblAboutMe.Text = aboutme.Length > 100 ? aboutme.Substring(0,100) + "..." : aboutme;
Do it with String.Substring(startIndex, lenght):
lblAboutMe.Text = DT1["UserBody"].ToString().Substring(0, 100) + " ...";
MSDN - Substring
If you want full words try following code. It determines null values and if it's larger than 100 chars. Than it makes shure a space is at the end:
int maxLength = 100;
string body = DT1["UserBody"] != null ? DT1["UserBody"].ToString() : "";
if (!string.IsNullOrEmpty(body))
{
if(body.Length > maxLength)
{
body = body.Substring(0, maxLength);
// if you want to have full words
if (body.Contains(" "))
{
while (body[body.Length - 1] != ' ')
{
body = body.Substring(0, body.Length - 1);
if(body.Length == 2)
{
break;
}
}
}
lblAboutMe.Text = body + "...";
}
else
{
lblAboutMe.Text = body;
}
}
Please also check for Null or empty string
string aboutme = Convert.ToString(DT1["UserBody"]);
if (!string.IsNullOrEmpty(aboutme))
{
lblAboutMe.Text = aboutme.Length > 100 ? aboutme.Substring(0, 100) +"..." : aboutme;
}
Basically, you use Substring but be aware of short texts with less than 100 characters
string test = /* your full string */;
string result = test.Substring(0, Math.Min(test.Length, 100)) + " ...";
If you want to cut at spaces, use IndexOf or if you want to consider all kinds of whitespace, you can do something along the lines of the following:
string result = test.Substring(0, Math.Min(test.Length, 100));
if (test.Length > 100)
{
result += new string(test.Substring(100).TakeWhile(x => !char.IsWhiteSpace(x)).ToArray()) + " ...";
}
I've been playing space engineers which has been epic since they added in-game programming, I'm trying to make a gps auto-pilot navigation script and have to get the block positions finding the blocks by name looking for a smaller string within their bigger string name. I wrote this method to find a small string (word) in a larger string (name of the block):
bool contains(string text, string wordInText)
{
char[] chText = text.ToCharArray();
char[] chWord = wordInText.ToCharArray();
int index = 0;
for(int i = 0 ; i < chText.Length - chWord.Length ; i++)
for(int j = 0; j < chWord.Length;j++,index++)
if (chWord[0] == chText[i])
index = i;
else if (chWord[j] == chText[index]){}
else if (index == chWord.Length-1)
return true;
else break;
return false;
}
Am I even doing it right, should I be doing it another shorter way?
This is simple with .Contains() which returns a bool.
text.Contains(wordInText);
If you simply want to check if a string contains an other string, then you can use string.Contains, the string class already provides a bunch of methods for string operations.
As already mentioned, the String class already has a Contains method that should give you what you need.
That said, your code doesn't work. I can see where you're going with it, but it's just not going to work. Stepping through it in a proper dev environment would show you why, but since this is more in the way of a script that's probably not an option.
So... the basic idea is to iterate through the string you're searching in, looking for matches against the string your searching. Your outer for statement looks fine for this, but your inner statements are a bit messed up.
Firstly, you're doing the first character check repeatedly. It's wasteful, and misplaced. Do it once per iteration of the outer loop.
Second, your exit condition is going to fire when the first character of wordInText matches the characters at index wordInText.Length in text which is not apparently what you want.
In fact you're all tripped up over the index variable. It isn't actually useful, so I'd drop it completely.
Here's a similar piece of code that should work. It is still much slower than the library String.Compare method, but hopefully it shows you how you might achieve the same thing.
for (int i = 0; i <= chText.Length - chWord.Length; i++)
{
if (chText[i] == chWord[0])
{
int j;
for (j = 0; j < chWord.Length; j++)
{
if (chText[i + j] != chWord[j])
break;
}
if (j == chWord.Length)
return true;
}
}
return false;
I want to write an application which sorts randomly line of text which I copy from a source and paste into RichTextBox area.
However, there is one condition - text is formatted (some words are in bold, underline etc.). So any suggestions? How should it look like?
I think I should use RichTextBox.Rtf or something but I am really a beginner and I appreciate every hint or example code.
Thanks
It is a bit tricky. You can retrieve the formatted RTF text lines like this
string[] rtfLines = new string[richTextBox1.Lines.Length];
for (int i = 0; i < rtfLines.Length; i++) {
int start = richTextBox1.GetFirstCharIndexFromLine(i);
int length = richTextBox1.Lines[i].Length;
richTextBox1.Select(start, length);
rtfLines[i] = richTextBox1.SelectedRtf;
}
Now you can shuffle the lines like this
var random = new Random();
rtfLines = rtfLines.OrderBy(s => random.NextDouble()).ToArray();
Clear the RichtTextBox
richTextBox1.Text = "";
Inserting the lines is best done in reverse order because it is easier to select the beginning of the text
// Insert the line which will be the last line.
richTextBox1.Select(0, 0);
richTextBox1.SelectedRtf = rtfLines[0];
// Prepend the other lines and add a line break.
for (int i = 1; i < rtfLines.Length; i++) {
richTextBox1.Select(0, 0);
// Replace the ending "}\r\n" with "\\par }\r\n". "\\par" is a line break.
richTextBox1.SelectedRtf =
rtfLines[i].Substring(0, rtfLines[i].Length - 3) + "\\par }\r\n";
}
The task seems not complicated(if I understand it correctly).
Get your clipboard into string then parse into array- use Split().
Then determine how many randon events you need and iterate through every word ; generate random number for each iteration(which should match the amount of events), intersect that number with one of the events and apply that case to that particular word. Maybe not the most efficient way to do it, but that's what comes to my mind
I have a RichTextBox, and there are about more than 1000 occurrences of a specified search string.
I use the following function to color all the occurrences:
public void ColorAll(string s)
{
rtbxContent.BeginUpdate();
int start = 0, current = 0;
RichTextBoxFinds options = RichTextBoxFinds.MatchCase;
start = rtbxContent.Find(s, start, options);
while (start >= 0)
{
rtbxContent.SelectionStart = start;
rtbxContent.SelectionLength = s.Length;
rtbxContent.SelectionColor = Color.Red;
rtbxContent.SelectionBackColor = Color.Yellow;
current = start + s.Length;
if (current < rtbxContent.TextLength)
start = rtbxContent.Find(s, current, options);
else
break;
}
rtbxContent.EndUpdate();
}
But I found it's very slow.
However, if I color all the occurrences of another word, which has less number of occurrences in the same text, I found it's very fast.
So I guess the slowness is from (these two line might get UI refresh involved):
rtbxContent.SelectionColor = Color.Red;
rtbxContent.SelectionBackColor = Color.Yellow;
Is there a faster way of doing the same job, such as, I do the coloring in the memory, and then I display the result at one-go?
Do I make myself clear?
Thanks.
The amount of time it takes is directly proportional to the number of occurances.
It is probably the Find that is using the most time. You could replace this line:
start = rtbxContent.Find(s, start + s.Length, options);
with this:
start = rtbxContent.Find(s, current, options);
Since you have computed current to equal start + s.Length
You could also store s.Length is a variable so you do not need to count all the characters in a string each time. The same goes for rtbxContent.TextLength.
There is a faster way.
Use regex to find the matches then highlight in the richtextbox
if (this.tBoxFind.Text.Length > 0)
{
try
{
this.richTBox.SuspendLayout();
this.Cursor = Cursors.WaitCursor;
string s = this.richTBox.Text;
System.Text.RegularExpressions.MatchCollection mColl = System.Text.RegularExpressions.Regex.Matches(s, this.tBoxFind.Text);
foreach (System.Text.RegularExpressions.Match g in mColl)
{
this.richTBox.SelectionColor = Color.White;
this.richTBox.SelectionBackColor = Color.Blue;
this.richTBox.Select(g.Index, g.Length);
}
}
finally
{
this.richTBox.ResumeLayout();
this.Cursor = Cursors.Default;
}
}
The string search is linear. If you find Find method to be slow, maybe you can use third party tool to do the searching for you. All you need is index of the pattern in a string.
Maybe this will help you. You should time the difference and use the faster one.
You're on the right track that Winforms' slow RichTextBox implementation is to blame. You also did well to use the BeginUpdate and EndUpdate methods (I'm guessing you took those from here?). But alas, that isn't enough.
A couple of solutions:
1: Try writing the RTF directly to the textbox. This is a fairly messy, complicated format, but luckily, I have created an answer here which will do the trick.
2: This highly rated external project also looks well worth a look: http://www.codeproject.com/Articles/161871/Fast-Colored-TextBox-for-syntax-highlighting