Using the access text escape. Use two underline characters if you want an underline to appear in your text.

  

<StackPanel xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="AccessTextSimple.Pane1">
  <StackPanel>
    <DockPanel Margin="30,10,3,3" >
      <Button Click="hello_Click">
        <AccessText>__He_llo__  Press the ALT key to see the access keys</AccessText>
      </Button>
    </DockPanel>

  </StackPanel>
</StackPanel>
//File:Window.xaml.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows;
using System.Windows.Controls;

namespace AccessTextSimple
{
  partial class Pane1 : StackPanel
  {
        public Pane1()
        {
            InitializeComponent();
        }

        void hello_Click(object sender, RoutedEventArgs e)
        {
            MessageBox.Show("button");
        }
    }
}

Related examples in the same category

1.	Using the AccessText element to create a label that has an access key and supports text wrapping.
2.	Setting AccessText properties.
3.	AccessText for TextBlock
4.	AccessText element adds access keys to controls.(how to specify the access key)

Using the access text escape. Use two underline characters if you want an underline to appear in your text. : AccessText « Windows Presentation Foundation « C# / C Sharp

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