tab size in the textbox

Question

Hey, is there any way to adjust the width in pixels of a tab character in the textbox? 

Answer 1

You could wire up to TextBox.PreviewKeyDown event to insert the specified number of white characters or tab characters as following code demonstrates:

<UserControl x:Class="AnswerHarness2.UserControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <TextBox AcceptsTab="True" AcceptsReturn="True" x:Name="textBox"/>
</UserControl>

public partial class UserControl1 : UserControl
{
    private int TabSize = 4;
    public UserControl1()
    {
        InitializeComponent();
        textBox.PreviewKeyDown += (sender, e) =>
        {
            if (e.Key == Key.Tab)
            {
                String tab = new String(' ', TabSize);
                textBox.Text.Insert(textBox.CaretIndex, tab);
            }
        };
    }
}

Hope this helps

Answer 2

Thanks for the hint, but I was hoping this could be controlled via a property (or a property of a property or something) without using codebehind.

Answer 3

Here you go:

public class MyTextBox : TextBox
{
    public MyTextBox()
    {
        //Defaults to 4
        TabSize = 4;
    }

    public int TabSize
    {
        get;
        set;
    }

    protected override void OnPreviewKeyDown(KeyEventArgs e)
    {
        if (e.Key == Key.Tab)
        {
            String tab = new String(' ', TabSize);
            int caretPosition = base.CaretIndex;
            base.Text = base.Text.Insert(caretPosition, tab);
            base.CaretIndex = caretPosition + TabSize + 1;
            e.Handled = true;
        }
    }
}

<cc:MyTextBox AcceptsReturn="True" TabSize="10" x:Name="textBox"/>

Hope this helps