Clear the text in multiple TextBox's at once

I have a WPF application with a Grid where there are multiple TextBoxs. How I can make开发者_StackOverflow社区 every TextBox.Text = null; with a button click?

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Give this a try:

   private void button1_Click(object sender, RoutedEventArgs e)
    {
        foreach (UIElement control in myGrid.Children)
        {
            if (control.GetType() == typeof(TextBox))
            {
                TextBox txtBox = (TextBox)control;
                txtBox.Text = null;
            }
        }
    }

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Something like this would work:

private void Button_Click(object sender, RoutedEventArgs e) {
    foreach (UIElement element in this.grid.Children) {
        TextBox textBox = element as TextBox;
        if (textBox == null)
            continue;

        textBox.Text = null;
    }
}

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The code Tom and CodeNaked gave will do what you want, but I would generally advise against this logic.

The Grid is there to help you organize your controls visually, it's a layout container. By no means it should be used to organize your controls logically, behind the scenes.

As I said, though, this is quite general advise. Your program might benefit from the other approach.

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There are multiple approaches to this problem.

The first is a hybrid approach where you would have the data flow down to your text boxes through bindings and a button click remove the data.

To start with you need to make sure your data classes implement INotifyPropertyChanged:

public class Foo : INotifyPropertyChanged
{
    private string bar;
    private string baz;

    public string Bar
    {
        get { return this.bar; }
        set
        {
            this.bar = value;

            // this is where the magic of bindings happens
            this.OnPropertyChanged("Bar");
        }
    }

    // rest of the class here...
}

Referenced in your XAML through bindings:

<Grid>
    <Grid.RowDefinitions>
        <!-- ... -->
    </Grid.RowDefinitions>
    <TextBox Grid.Row="0"
             Text="{Binding Bar}" />
    <TextBox Grid.Row="1"
             Text="{Binding Baz}" />

    <!-- A more complete example would use Button.Command -->
    <Button Grid.Row="2"
            Content="CLEAR"
            Click="ClearButton_Click" />

Finally, these bindings are wired up using the DataContext and a routed event handler in your Windows code-behind:

public Window1()
{
    this.InitializeComponent();

    // sets up the DataContext used by the bindings
    this.Clear();
}

private void ClearButton_Click(object sender, RoutedEventArgs e)
{
    this.Clear();
}

private void Clear()
{
    this.DataContext = new Foo();
}

This approach will push you in a better direction to handle more complicated UI's.

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A last ditch effort would be:

/// <summary>This is a bad choice.</summary>
private void ClearButton_Click(object sender, RoutedEventArgs e)
{
    // assumes the Grid is named MyGrid
    foreach (var textBox in this.MyGrid.Children.OfType<TextBox>())
    {
        textBox.Text = null;
    }
}