I am using C# WinForm, and I have a RichTextBox that I am trying to make look like a C# script.
Means when using specific words, I want them to be colored. When they edit the word by changing it, I want it to go back to be black.
My approach works, but it really messy and cause bugs when the a scroll option is created and needed to be used to see the code below. (When typing, pretty much the richtextbox jumps up and down without stop)
private void ScriptRichTextBox_TextChanged(object sender, EventArgs e)
{
ScriptTextChange = ScriptRichTextBox.Text;
ScriptColorChange();
}
private void ScriptColorChange()
{
int index = ScriptRichTextBox.SelectionStart;
ScriptRichTextBox.Text = ScriptTextChange; //Only way I found to make the all current text black again, SelectAll() didn't work well.
ScriptRichTextBox.SelectionStart = index;
String[] coloredNames = {"Main", "ClickMouseDown", "ClickMouseUp", "PressKey", "StopMoving", "Delay", "GoRight", "GoLeft", "GoUp", "GoDown", "MousePosition", "LastHorizontalDirection", "LastVerticalDirections", "CurrentDirection", "Directions" };
String[] coloredNames2 = { "cm.", "if", "else", "while", "switch", "case", "break", "return", "new" };
String[] coloredNames3 = { "MyPosition", "MyHp", "MyMp", "OtherPeopleInMap", ".RIGHT", ".LEFT", ".UP", ".DOWN", ".STOP_MOVING" };
foreach (String s in coloredNames)
this.CheckKeyword(s, Color.LightSkyBlue, 0);
foreach (String s in coloredNames2)
this.CheckKeyword(s, Color.Blue, 0);
foreach (String s in coloredNames3)
this.CheckKeyword(s, Color.DarkGreen, 0);
}
private void CheckKeyword(string word, Color color, int startIndex)
{
if (this.ScriptRichTextBox.Text.Contains(word))
{
int index = 0;
int selectStart = this.ScriptRichTextBox.SelectionStart;
while ((index = this.ScriptRichTextBox.Text.IndexOf(word, (index + 1))) != -1)
{
this.ScriptRichTextBox.Select((index + startIndex), word.Length);
this.ScriptRichTextBox.SelectionColor = color;
this.ScriptRichTextBox.Select(selectStart, 0);
this.ScriptRichTextBox.SelectionColor = Color.Black;
}
}
}
I refactored your code a little to hopefully demonstrate a better approach to colouring the text. It is also not optimal to instantiate your string arrays every time you fire the TextChanged event.
Updated:The idea is to build up a word buffer that will be matched with your set of words when typing.
The buffer records each key and if it .IsLetterOrDigit it adds it to the StringBuilder buffer. The buffer has some additional bugs, with recording key press values and not removing recorded chars if you hit backspace etc..
Instead of the word buffer, use RegEx to match any of the words in your reserve word list. Build up the reserve word RegEx so you end up with something like \b(word|word2|word3....)\b This is done in the code in the BuildRegExPattern(..) method.
Once you hit any key other than a letter or number the buffer is checked for content and if the content matches a word then only the text right before the cursor in the ScriptRichTextBox.Text is checked and changed.
Remove the .(dots) from the reserve words as this just complicates the matching criteria. The RegEx in the built up patters will match the words exactly, so if you type something like FARRIGHT or cms the words will not partially change colour.
As an extra I also covered the paste process pressing Ctrl+V because it is a bit of a pain in WinForms and will probably happen quite often.
There are older questions eg. this one that cover the scrolling behaviour, where it shows how to interop by adding the [System.Runtime.InteropServices.DllImport("user32.dll")] attribute, but it can be done without it.
To prevent all the scroll jumping you can make use of the .DefWndProc(msg) method on the form. this question pointed me towards the WM_SETREDRAW property.
There is also this list of other properties that can be set.
The full implementation is this:
public partial class Form1 : Form
{
private readonly string[] _skyBlueStrings;
private readonly string[] _blueStrings;
private readonly string[] _greenStrings;
//for pasting
bool _IsCtrl;
bool _IsV;
//value to fix the colour not setting first character after return key pressed
int _returnIdxFix = 0;
//regex patterns to use
string _LightBlueRegX = "";
string _BlueRegX = "";
string _GreenRegX = "";
//match only words
Regex _rgxAnyWords = new Regex(#"(\w+)");
//colour setup
Color _LightBlueColour = Color.LightSkyBlue;
Color _BlueColour = Color.Blue;
Color _GreenColour = Color.DarkGreen;
Color _DefaultColour = Color.Black;
public Form1()
{
InitializeComponent();
_skyBlueStrings = new string[] { "Main", "ClickMouseDown", "ClickMouseUp", "PressKey", "StopMoving", "Delay", "GoRight", "GoLeft", "GoUp", "GoDown", "MousePosition", "LastHorizontalDirection", "LastVerticalDirections", "CurrentDirection", "Directions" };
_blueStrings = new string[] { "cm", "if", "else", "while", "switch", "case", "break", "return", "new" };
_greenStrings = new string[] { "MyPosition", "MyHp", "MyMp", "OtherPeopleInMap", "RIGHT", "LEFT", "UP", "DOWN", "STOP_MOVING" };
_LightBlueRegX = BuildRegExPattern(_skyBlueStrings);
_BlueRegX = BuildRegExPattern(_blueStrings);
_GreenRegX = BuildRegExPattern(_greenStrings);
}
string BuildRegExPattern(string[] keyworkArray)
{
StringBuilder _regExPatern = new StringBuilder();
_regExPatern.Append(#"\b(");//beginning of word
_regExPatern.Append(string.Join("|", keyworkArray));//all reserve words
_regExPatern.Append(#")\b");//end of word
return _regExPatern.ToString();
}
private void ProcessAllText()
{
BeginRtbUpdate();
FormatKeywords(_LightBlueRegX, _LightBlueColour);
FormatKeywords(_BlueRegX, _BlueColour);
FormatKeywords(_GreenRegX, _GreenColour);
//internal function to process words and set their colours
void FormatKeywords(string regExPattern, Color wordColour)
{
var matchStrings = Regex.Matches(ScriptRichTextBox.Text, regExPattern);
foreach (Match match in matchStrings)
{
FormatKeyword(keyword: match.Value, wordIndex: match.Index, wordColour: wordColour);
}
}
EndRtbUpdate();
ScriptRichTextBox.Select(ScriptRichTextBox.Text.Length, 0);
ScriptRichTextBox.Invalidate();
}
void ProcessWordAtIndex(string fullText, int cursorIdx)
{
MatchCollection anyWordMatches = _rgxAnyWords.Matches(fullText);
if (anyWordMatches.Count == 0)
{ return; } // no words found
var allWords = anyWordMatches.OfType<Match>().ToList();
//get the word just before cursor
var wordAtCursor = allWords.FirstOrDefault(w => (cursorIdx - _returnIdxFix) == (w.Index + w.Length));
if (wordAtCursor is null || string.IsNullOrWhiteSpace(wordAtCursor.Value))
{ return; }//no word at cursor or the match was blank
Color wordColour = CalculateWordColour(wordAtCursor.Value);
FormatKeyword(wordAtCursor.Value, wordAtCursor.Index, wordColour);
}
private Color CalculateWordColour(string word)
{
if (_skyBlueStrings.Contains(word))
{ return _LightBlueColour; }
if (_blueStrings.Contains(word))
{ return _BlueColour; }
if (_greenStrings.Contains(word))
{ return _GreenColour; }
return _DefaultColour;
}
private void FormatKeyword(string keyword, int wordIndex, Color wordColour)
{
ScriptRichTextBox.Select((wordIndex - _returnIdxFix), keyword.Length);
ScriptRichTextBox.SelectionColor = wordColour;
ScriptRichTextBox.Select(wordIndex + keyword.Length, 0);
ScriptRichTextBox.SelectionColor = _DefaultColour;
}
#region RichTextBox BeginUpdate and EndUpdate Methods
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
//wait until the rtb is visible, otherwise you get some weird behaviour.
if (ScriptRichTextBox.Visible && ScriptRichTextBox.IsHandleCreated)
{
if (m.LParam == ScriptRichTextBox.Handle)
{
rtBox_lParam = m.LParam;
rtBox_wParam = m.WParam;
}
}
}
IntPtr rtBox_wParam = IntPtr.Zero;
IntPtr rtBox_lParam = IntPtr.Zero;
const int WM_SETREDRAW = 0x0b;
const int EM_HIDESELECTION = 0x43f;
void BeginRtbUpdate()
{
Message msg_WM_SETREDRAW = Message.Create(ScriptRichTextBox.Handle, WM_SETREDRAW, (IntPtr)0, rtBox_lParam);
this.DefWndProc(ref msg_WM_SETREDRAW);
}
public void EndRtbUpdate()
{
Message msg_WM_SETREDRAW = Message.Create(ScriptRichTextBox.Handle, WM_SETREDRAW, rtBox_wParam, rtBox_lParam);
this.DefWndProc(ref msg_WM_SETREDRAW);
//redraw the RichTextBox
ScriptRichTextBox.Invalidate();
}
#endregion
private void ScriptRichTextBox_TextChanged(object sender, EventArgs e)
{
//only run all text if it was pasted NOT ON EVERY TEXT CHANGE!
if (_IsCtrl && _IsV)
{
_IsCtrl = false;
ProcessAllText();
}
}
protected void ScriptRichTextBox_KeyPress(object sender, KeyPressEventArgs e)
{
if (!char.IsLetterOrDigit(e.KeyChar))
{
//if the key was enter the cursor position is 1 position off
_returnIdxFix = (e.KeyChar == '\r') ? 1 : 0;
ProcessWordAtIndex(ScriptRichTextBox.Text, ScriptRichTextBox.SelectionStart);
}
}
private void ScriptRichTextBox_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (e.KeyCode == Keys.ControlKey)
{
_IsCtrl = true;
}
if (e.KeyCode == Keys.V)
{
_IsV = true;
}
}
private void ScriptRichTextBox_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (e.KeyCode == Keys.ControlKey)
{
_IsCtrl = false;
}
if (e.KeyCode == Keys.V)
{
_IsV = false;
}
}
}
It looks like this when you paste some "code" with keywords:
and typing looks like this:
Ok after 2 days of not finding something that actually works good or has annoying bugs. I managed to find a solution myself after a big struggle of trying to make it work. The big idea is people try to edit all the RichTextBox words at once, which cause bugs. Why to edit all of the rich text box when you can do your checks on the current word only to get the same result. Which is what I did, I checked if any of my array strings is in the current word, and colored all of them.
private void ScriptRichTextBox_TextChanged(object sender, EventArgs e)
{
FindStringsInCurrentWord();
}
private void FindStringsInCurrentWord()
{
RichTextBox script = ScriptRichTextBox;
String finalWord, forwards, backwards;
int saveLastSelectionStart = script.SelectionStart;
int index = script.SelectionStart;
String[] coloredNames = { "Main", "ClickMouseDown", "ClickMouseUp", "PressKey", "StopMoving", "Delay", "GoRight", "GoLeft", "GoUp", "GoDown", "MousePosition", "LastHorizontalDirection", "LastVerticalDirections", "CurrentDirection", "Directions" };
String[] coloredNames2 = { "cm.", "if", "else", "while", "switch", "case", "break", "return", "new" };
String[] coloredNames3 = { "MyPosition", "MyHp", "MyMp", "OtherPeopleInMap", ".RIGHT", ".LEFT", ".UP", ".DOWN", ".STOP_MOVING" };
String[] arr2 = coloredNames.Union(coloredNames2).ToArray();
Array arrAll = arr2.Union(coloredNames3).ToArray(); //Gets all arrays together
Array[] wordsArray = { coloredNames, coloredNames2, coloredNames3 }; //All found strings in the word
List<String> wordsFoundList = new List<String>();
int foundChangedColor = 0;
int wordsFound = 0;
char current = (char)script.GetCharFromPosition(script.GetPositionFromCharIndex(index)); //Where the editor thingy is
//Check forward text where he uses space and save text
while (!System.Char.IsWhiteSpace(current) && index < script.Text.Length)
{
index++;
current = (char)script.GetCharFromPosition(script.GetPositionFromCharIndex(index));
}
int lengthForward = index - saveLastSelectionStart;
script.Select(script.SelectionStart, lengthForward);
forwards = script.SelectedText;
//Debug.WriteLine("Forwards: " + forwards);
script.SelectionStart = saveLastSelectionStart;
this.ScriptRichTextBox.Select(script.SelectionStart, 0);
index = script.SelectionStart;
current = (char)script.GetCharFromPosition(script.GetPositionFromCharIndex(index));
int length = 0;
//Check backwords where he uses space and save text
while ((!System.Char.IsWhiteSpace(current) || length == 0) && index > 0 && index <= script.Text.Length)
{
index--;
length++;
current = (char)script.GetCharFromPosition(script.GetPositionFromCharIndex(index));
}
script.SelectionStart -= length;
script.Select(script.SelectionStart + 1, length - 1);
backwards = script.SelectedText;
//Debug.WriteLine("Backwards: " + backwards);
script.SelectionStart = saveLastSelectionStart;
this.ScriptRichTextBox.Select(saveLastSelectionStart, 0);
this.ScriptRichTextBox.SelectionColor = Color.Black;
finalWord = backwards + forwards; //Our all word!
//Debug.WriteLine("WORD:" + finalWord);
//Setting all of the word black, after it coloring the right places
script.Select(index + 1, length + lengthForward);
script.SelectionColor = Color.Black;
foreach (string word in arrAll)
{
if (finalWord.IndexOf(word) != -1)
{
wordsFound++;
wordsFoundList.Add(word);
script.Select(index + 1 + finalWord.IndexOf(word), word.Length);
if (coloredNames.Any(word.Contains))
{
script.SelectionColor = Color.LightSkyBlue;
foundChangedColor++;
}
else if (coloredNames2.Any(word.Contains))
{
script.SelectionColor = Color.Blue;
foundChangedColor++;
}
else if (coloredNames3.Any(word.Contains))
{
script.SelectionColor = Color.DarkGreen;
foundChangedColor++;
}
//Debug.WriteLine("Word to edit: " + script.SelectedText);
this.ScriptRichTextBox.Select(saveLastSelectionStart, 0);
this.ScriptRichTextBox.SelectionColor = Color.Black;
}
}
//No strings found, color it black
if (wordsFound == 0)
{
script.Select(index + 1, length + lengthForward);
script.SelectionColor = Color.Black;
//Debug.WriteLine("WORD??: " + script.SelectedText);
this.ScriptRichTextBox.Select(saveLastSelectionStart, 0);
this.ScriptRichTextBox.SelectionColor = Color.Black;
}
}
Target:
To write in the label text, but the label ID is assigned by a string.
Problem:
It doesn't work, no errors given. I looked in most places for an answer but nothing helped!
My Code:
string asdfj = treeView2.SelectedNode.Text;
string adqien = System.IO.Path.Combine(dir7, asdfj);
string[] tnsop = System.IO.File.ReadAllLines(#adqien);
h1a.Text = "100";
for (int o = 2; o > 6; o++)
{
//This is the label name e.g "h2a',h3a" etc
string tempc = string.Format("h" + o.ToString() + "a");
foreach (Control ctr in this.Controls)
{
if (ctr is Label)
{
if (ctr.Name == tempc)
{
ctr.Text = tnsop[o];
}
}
}
}
I also consulted this post:
Use string variable content as label ID to update label.Text, I get error - 'string' does not contain a definition for 'Text'
You can do it simply like:
this.Controls.Find(labelname).Text = Value;
or
this.Controls.OfType<Label>().FirstOrDefault(x => x.Name == labelName).Text = Value;
The for loop
First of all, this is wrong for (int o = 2; o > 6; o++).
It starts at o = 2, then checks if o > 6, which is false, because o = 2, and then skips the loop.
I guess you wanted to write: for (int o = 2; o < 6; o++). I am not sure about that, fix it as appropiate.
Addendum: This would have been easily discovored by debugging and stepping. You can start by adding a break point on your code (in Visual Studio you can place your cursor on the desired line and press F9 - by default) and then run in the debugger. When the a line with the break point is reached, the debbuger stops the execution and let you inspect the values of the variables, the call stack, etc. You can then step with F10 or F11 (if you want to inside a method call) and see how the code evolves. You would notice it does not enter the for loop.
Finding the labels
If finding the label still does not work, I would guess the problem is that the labels are not directly on the form or that they do not have the given name.
You can use this.Controls.Find(name, searchAllChildren) to get the labels you need.
That is:
string labelName = string.Format("h" + o.ToString() + "a");
Control[] control = this.Controls.Find(labelName, true);
Note: Yes, I can figure out it is the name of the label by how you use it. Using a comment to tell me saves some time... however, please use better variable names. You won't need a comment to tell me this is the name of the label if the variable name says so.
You still need to check it for the label:
string labelName = string.Format("h" + o.ToString() + "a");
Control[] controls = this.Controls.Find(labelName, true);
foreach (Control control in controls)
{
if (control is Label) // if (control.GetType() == typeof(Label))
{
// ...
}
}
Building a Dictionary
However, I would advice against doing this every time. Instead, I suggest to build a dictionary:
Dictionary<string, Label> labels;
// ...
labels = new Dictionary<string, Label>();
for(int o = 2; o < 6; o++)
{
string labelName = string.Format("h" + o.ToString() + "a");
Label label = GetLabel(labelName);
labels.Add(labelName, label);
}
// ...
private Label GetLabel(string labelName)
{
Control[] controls = this.Controls.Find(labelName, true);
foreach (Control control in controls)
{
if (control is Label) // if (control.GetType() == typeof(Label))
{
return control as Label;
}
}
return null;
}
Note: I suggest to make the dictionary a field and initialize it only once during the form load.
This separates the responsability of finding the labels from reading the file (which is external to the program). Allowing you to test if it can find the right controls without the need of a file.
It will also make the case where the Label is not found visible (we just added a null to the dictionary).
And then use it:
string[] tnsop = System.IO.File.ReadAllLines(#adqien);
for (int o = 2; o < 6; o++)
{
string labelName = string.Format("h" + o.ToString() + "a");
label = labels[labelName];
label.Text = tnsop[o];
}
The code above should throw NullReferenceException if the label was not found while building the dictionary.
Simplify
I guess we can do better. The designer will create fields for your labels, you can just add them to the dictionary:
Dictionary<string, Label> labels;
// ...
labels = new Dictionary<string, Label>();
labels["h2a"] = h2a;
labels["h3a"] = h3a;
labels["h4a"] = h4a;
labels["h5a"] = h5a;
// ...
string[] tnsop = System.IO.File.ReadAllLines(#adqien);
for (int o = 2; o < 6; o++)
{
string labelName = string.Format("h" + o.ToString() + "a");
label = labels[labelName];
label.Text = tnsop[o];
}
Note: There are plenty of opportunities for more modern syntax, including collection initialization and the var keyword.
Addendum: I am unrolling the loop in the above code, this is ok for maintainability if the number of iterations small, in fact, it is a common optimization. You could, in theory do it for the other loop too.
PS. An array will do
I noticed, after finishing writing, that the code only needs to look up by an int o.
We can rework to use int for dictionary keys:
Dictionary<int, Label> labels;
// ...
labels = new Dictionary<int, Label>();
labels[2] = h2a;
labels[3] = h3a;
labels[4] = h4a;
labels[5] = h5a;
// ...
string[] tnsop = System.IO.File.ReadAllLines(#adqien);
for (int o = 2; o < 6; o++)
{
label = labels[o];
label.Text = tnsop[o];
}
Now we have less concatenations, and a simpler code.
We could, in fact, be using an array:
Label[] labels;
// ...
labels = new Label[4];
labels[0] = h2a;
labels[1] = h3a;
labels[2] = h4a;
labels[3] = h5a;
// ...
string[] tnsop = System.IO.File.ReadAllLines(#adqien);
for (int o = 2; o < 6; o++)
{
label = labels[o - 2];
label.Text = tnsop[o];
}
Notice I did offset the indexes to be able to use the array from index 0.
I want to get the text between ';' character. However if there are 3 matches like that, i want to get the text between ';' character where current cursor position. I am using multine textbox.
Example;
select * from database;
----> **Lets say my cursor is here**
select
orders from
customer;
select * from employees;
So, i only want to get 'select orders from customer' text.
Could you please share your thoughts on it?
To achieve this, you first have to find all indicies of ;. To do this, iterate through all indicies (source):
private List<int> AllIndicesOf(string strToSearch, string fullText)
{
List<int> foundIndices = new List<int>();
for (int i = fullText.IndexOf(strToSearch); i > -1; i = fullText.IndexOf(strToSearch, i + 1))
{
foundIndices.Add(i + 1);
}
return foundIndices;
}
Then you have to compare your position to those indices, since you only want the index (of ;) that follows immediately after your cursor:
List<int> indicies = AllIndicesOf(";", txtBxText.Text);
try
{
if (indicies.Count > 0)
{
int cursorPos = txtBxText.SelectionStart;
var indicesBefore = indicies.Where(x => x < cursorPos);
int beginIndex = indicesBefore.Count() > 0 ? indicesBefore.Last() : 0;
int endIndex = indicies.Where(x => x > beginIndex).First();
txtBxSelected.Text = txtBxText.Text.Substring(beginIndex, endIndex - beginIndex);
}
}
catch { }
The try-catch statement is used to prevent an Exception if your cursors position is after all other indices.
A sample project can be downloaded here.
This solution perfectly works although you need to check it again and consider some possible exceptions. I did not consider them myself because I thought it was better to be handled by you. I also used richTextBox which is better than the multi line text box. Enjoy the code bro
private void button1_Click(object sender, EventArgs e)
{
var ultimateResult = string.Empty;
var cusrPosition = richTextBox1.SelectionStart;
var currentStr = string.Empty;
var strDic = new Dictionary<string,int>();
var textArr = richTextBox1.Text.ToCharArray();
for (var i = 0; i < textArr.Count(); i++)
{
if (textArr[i] != ';')
currentStr = currentStr + textArr[i];
else
{
strDic.Add(currentStr,i);
currentStr = string.Empty;
}
}
ultimateResult = strDic.First(item => item.Value >= cusrPosition).Key;
textBox1.Text = ultimateResult;
}
im looping on 24 picturebox on groupbox for displaying something, but it doesn't loop in the right order, it may start at the 18th picture box and here is the code im using
foreach (var pb in groupBox1.Controls)
{
if (pb is PictureBox && previewIndexer < Previewer.Count)
{
try
{
((PictureBox)pb).Image = ...
previewIndexer++;
...
}
catch
{
...
}
}
}
i would want to loop in ascending order of which it loops on picturebox1 first till picturebox24, thanks and have wonderful day
Your problem is ordering controls by name. You need alphanumeric sorting in order to picturebox10 go after picturebox5. This can be done if you will sort pictureboxes by numbers in their names:
foreach (var pb in groupBox1.Controls.OfType<PictureBox>()
.OrderBy(x => Int32.Parse(x.Name.Substring("picturebox".Length))))
{
pb.Image = ...;
}
I would even created some method like (it removes all non-numeric characters from control name and tries to parse rest to integer value):
private int GetControlId(Control control)
{
int id;
string idToParse = Regex.Replace(control.Name, #"\D+", "");
return Int32.TryParse(idToParse, out id) ? id : 0;
}
And used this method in query
var pictureBoxes = groupBox1.Controls.OfType<PictureBox>();
foreach (var pb in pictureBoxes.OrderBy(GetControlId))
{
pb.Image = ...;
}
You can take benefit of LINQ here, suppose you named your pictureboxes as picture1, picture2, ...
foreach (var pb in groupBox1.Controls.OfType<PictureBox>().OrderBy(p=>int.Parse(Regex.Replace(k,"\\D*",""))))
{
if(previewIndexer < Previewer.Count) {
try
{
((PictureBox)pb).Image = ...
previewIndexer++;
...
}
catch
{
...
}
}
}
You can index the Controls property with a string which refers to the name of the control.
This might be the simpliest solution:
for (int i = 1; i <= 24; i++)
{
PictureBox pb = groupBox1.Controls["picturebox" + i.ToString()] as PictureBox;
}
I have a Navigation-bar in my program that allows you to navigate the different sections in my TextBox, but the problem I have is that this doesn't work if the Text I am scrolling to is already visible on the screen.
Like in this example, if I try to jump from Section 1 to Section 3, it won't work as it's already visible.
But, in this example if I jump to Section 3, it works fine as it's not already visible.
The scrolling function I use is very simple:
if (nLine > 0 && nLine <= textBox.LineCount)
textBox.ScrollToLine(nLine - 1);
I hope that someone can shed some light on an alternative solution that allows me to scroll even if the text is already visible.
Edit: Added solution.
This is a code snippet from my project.
private static void ScrollToLineCallback(DependencyObject target, DependencyPropertyChangedEventArgs e)
{
var textBox = (TextBox)target;
int newLineValue;
if (Int32.TryParse(e.NewValue.ToString(), out newLineValue))
{
if (newLineValue > 0 && newLineValue <= textBox.LineCount) // Validate
{
textBox.ScrollToLine(newLineValue - 1); // Scroll to Line
// Check and see if we are at the line we want.
if (textBox.GetFirstVisibleLineIndex() <= newLineValue && textBox.GetLastVisibleLineIndex() >= newLineValue)
{
// If not lets move to the desired location
int newLineCorrectionValue = newLineValue - textBox.GetFirstVisibleLineIndex() - 2; // How much further do we need to scroll down?
for (int i = 0; i < newLineCorrectionValue; i++)
{
textBox.LineDown(); // Scroll down
}
}
}
}
}
You could use GetCharacterIndexFromLineIndex to get the index of the beginning of the desired line and then set the CaretIndex to that value.
Because I don't really know, what you are trying to achieve, another possibility is to use LineUp and LineDown in conjunction with GetFirstVisibleLineIndex and GetLastVisibleLineIndex.
private void TextBoxGotoLine(
TextBox textbox1,
int linenum)
{
var target_cpos = textbox1.GetCharacterIndexFromLineIndex(linenum);
var target_char_rect = textbox1.GetRectFromCharacterIndex(target_cpos);
var first_char_rect = textbox1.GetRectFromCharacterIndex(0);
textbox1.ScrollToVerticalOffset(
target_char_rect.Top -
first_char_rect.Top
);
}
I found out if Wrapping is enabled its more complications:
private void TextBoxGotoLine(TextBox textbox1, int linenum)
{
// int Linenum is the Absolute Line, not including
// effect of Textbox Wrapping.
if (textbox1.TextWrapping == TextWrapping.Wrap)
{
// If textbox Wrapping is on, we need to
// Correct the Linenum for Wrapping which adds extra lines
int cidx = 0;
bool found = false;
int ln = 0;
char[] tmp = textbox1.Text.ToCharArray();
for (cidx = 0; cidx < tmp.Length; cidx++)
{
if (tmp[cidx] == '\n')
{
ln++;
}
if (ln == linenum)
{
found = true;
break;
}
}
if (!found)
return;
linenum = textbox1.GetLineIndexFromCharacterIndex(cidx+1);
}
// Non-Wrapping TextBox
var target_cpos = textbox1.GetCharacterIndexFromLineIndex(linenum);
var target_char_rect = textbox1.GetRectFromCharacterIndex(target_cpos);
var first_char_rect = textbox1.GetRectFromCharacterIndex(0);
textbox1.ScrollToVerticalOffset(target_char_rect.Top - first_char_rect.Top);
}