I need to be able to scroll a RichTextBox to the bottom, even when I am not appending text. I know I can append text, and then use that to set the selection start. However I want to ensure it is at the bottom for visual reasons, so I am not adding any text.
You could try setting the SelectionStart property to the length of the text and then call the ScrollToCaret method.
richTextBox.SelectionStart = richTextBox.Text.Length;
richTextBox.ScrollToCaret();
The RichTextBox will stay scrolled to the end if it has focus and you use AppendText to add the information. If you set HideSelection to false it will keep its selection when it loses focus and stay auto-scrolled.
I designed a Log Viewer GUI that used the method below. It used up to a full core keeping up. Getting rid of this code and setting HideSelection to false got the CPU usage down to 1-2%.
//Don't use this!
richTextBox.AppendText(text);
richTextBox.ScrollToEnd();
In WPF you can use ScrollToEnd:
richTextBox.AppendText(text);
richTextBox.ScrollToEnd();
Code should be written in the rich text box's TextChanged event like :
private void richTextBox_TextChanged(object sender, EventArgs e) {
richTextBox.SelectionStart = richTextBox.Text.Length;
richTextBox.ScrollToCaret();
}
Related
I have a RichTextBox. I'm working on changing the SelectionBackColor only of the selected text.
Then, I have a ToolStripMenuItem(let's call it 'buttonA' for now) which is responsible to change the SelectionBackColor of the selected text. The problem I'm facing is after I click buttonA, the background color of the selected text in the RichTextBox can be successfully done. However, when I add some other characters or text right after the changed background color text, it doesn't use the default background color. Instead, it continues to use the same background color as assigned from buttonA, which I don't want to happen.
At first, I thought that my start index and end index of the selected text was problematic. But, I don't think there's any problems in its codes. Below shows the code example:
SolidBrush textBgCol; //a variable to keep color
this.richTextBox1.Select = this.richTextBox1.SelectionStart, this.richTextBox1.SelectionLength;
this.richTextBox1.SelectionBackColor = Color.FromArgb(textBgCol.Color.A, textBgCol.Color.R, textBgCol.Color.G, textBgCol.Color.B);
One of my efforts was to change the SelectionBackColor to default in the KeyDown event of richTextBox1. However, the background color of the new or successive characters and text were still the same as assigned from buttonA. Below shows the code example:
private void richTextBox1_KeyDown(object sender, KeyEventArgs e)
{
this.richTextBox1.SelectionBackColor = default;
}
I've also tried to refer to this but, I don't think it helps me to solve my case here.
Other than that, just to confirm that my richTextBox1's SelectionStart and SelectionLength were okay, I've even referred to these: ref1, ref2, and ref3.
May I know any other workarounds for this please? Or, were there anything inside my codes that I've missed?
Based on comment by #Jimi:
I just need to change the codes in my richTextBox1's KeyDown event handler to:
if(richTextBox1.SelectionBackColor != richTextBox1.BackColor)
{
richTextBox1.SelectionBackColor = richTextBox1.BackColor;
}
Below shows the demo:
Thanks!
after a long search on the net, I hope you can help me.
My Problem:
I want to select the complete text in a TextBox
and will show the caret (blinking cursor) after the last character.
Always I have found information about one problem or information to hide the caret.
The separate things are no problems but the combination of it don't work.
// Set the focus to the TextBox
myTextBox.Focus();
// Select the complete text, but hide the caret (blinking cursor)
myTextBox.SelectAll();
// or
// myTextBox.Select(0, myTextBox.Text.Length);
// Set the caret after the last character, but loss the selection from the text
myTextBox.CaretIndex = myTextBox.Text.Length;
So, I see the caret after the last character, but the text is not selected
myTextBox.Focus();
myTextBox.SelectAll();
myTextBox.CaretIndex = myTextBox.Text.Length;
And so, the text is selected, but no caret is shown.
myTextBox.Focus();
myTextBox.CaretIndex = myTextBox.Text.Length;
myTextBox.SelectAll();
And that's the problem: one of them deactivate the another one, but I need these two things at the same time
I using WPF and .Net 4.0
Thanks for helping :-)
The problem is the strong internal connection in the TextBox between CaretIndex and the Selection.
Whenever you modify the selection with Select() or SelectAll(), the TextBox automatically places the CaretIndex at the beginning of the selection. In reverse, the TextBox clears the selection when you manually modify the CaretIndex. You can make this behavior visible, if you register for SelectionChanged in the TextBox and output the current CaretIndex to Console.
This is for a good reason, as Okuma.Scott already mentioned in his comment.
So if your desired behaviour is really required, you probably need to implement your own CustomTextBox.
This worked for me:
TextBox.Text = _Text;
System.Windows.Input.Keyboard.Focus(TextBox);
TextBox.GotFocus += (sender, e) => {
if (_selectAll)
{
//I think Caret can be set here but I didn't try it
TextBox.SelectAll();
}
};
So I'm using this code which moves the cursor to the end of the text box content each time I'm adding something to it.
void txtDisplay_TextChanged(object sender, EventArgs e)
{
txtDisplay.SelectionStart = txtDisplay.Text.Length;
txtDisplay.ScrollToCaret();
txtDisplay.Refresh();
}
The problem is that I see like flickering of text box scroll bar which goes up and down each time I add something to the text box. Doing this 10 times a second seems like it consumes some processing power and it looks ugly.
How to keep the scroll bar scrolled down all the time?
Hi there ( again :) ),
I've just looked for some methods to avoid this flickering and I found this post exploring both SelectedText property and AppendText() method, with the lattest actually appending the text and scrolling only if it's necessary.
Hope that'll help !
I have a multiline TextBox called Console. While running, this textbox is being filled up with some communications data. I use
TextBox.AppendText("txt\r\n");
to add a line to it and that allows me to have it autoscroll down. My problem is I want to be able to not have it autoscroll down. So I thought I would try
TextBox.Text += "text";
But that scrolls you to the beginning of the box. My latest attempt was to use TextBox.SelectionStart to save the position before I wrote and restore it back to that after, but that didn't seem to make a difference and still brings me back to the beginning of the text.
int txtPosition = Console.SelectionStart;
Console.Text += "TextToAdd";
Console.SelectionStart = txtPosition;
Ideally I want to just be able to have the box stay where ever it happens to be and not scroll to the beginning or end of the text.
I think you need to you a richtextbox instead of a generic textbox and this will provide you with the functionality you desire.
Enjoy!
For a WinForms textbox, you may should able to do this:
textBox.SelectionStart = 0;
textBox.ScrollToCaret(); // force current position back to top
I've got a simple form with RichTextBox on it. In Load event, I write some text to RichTextBox and now I want to set cursor location to the end of this text so I can add something. I've tried Focus() but it doesn't work
Try :
richTextBox1.SelectionStart = richTextBox1.Text.Length;
richTextBox1.Focus();
You can either use the CaretPosition property or use the Select(pos, pos) method to achieve the desired result.
Edit:
The Focus method just moves the keyboard focus to your RichTextBox, but it doesn't alter the current position of the cursor inside the control.
For winform application simple add this command SendKeys.Send("{RIGHT}"); after richTextBox1.AppendText("foo"); or richTextBox1.Paste(); then `richTextBox1.Focus();'