Question

I have the following ControlTemplate:

<ControlTemplate>
    <Grid VerticalAlignment="Stretch" HorizontalAlignment="Left" Width="400">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="18" />
            <ColumnDefinition Width="20*" />
            <ColumnDefinition Width="20*" />
            <ColumnDefinition Width="20*" />
            <ColumnDefinition Width="45" />
        </Grid.ColumnDefinitions>
        <TextBox Grid.Column="1" Template="{StaticResource watermark}" HorizontalAlignment="Stretch" Margin="4,0,0,4" Tag="Number" />
        <TextBox Grid.Column="2" Template="{StaticResource watermark}" HorizontalAlignment="Stretch" Margin="4,0,0,4" Tag="Login" />
        <TextBox Grid.Column="3" Template="{StaticResource watermark}" HorizontalAlignment="Stretch" Margin="4,0,0,4" Tag="Password" />
        <Button Grid.Column="4" HorizontalAlignment="Stretch" Content="Add" Margin="4,0,0,4" Click="AddUser_Click"/>
    </Grid>
</ControlTemplate>

How should I write AddUser_Click to get access to textboxes Text properties?

upd: just to make it clear. I know how to connect Click event handler here. The question is how to read contents of textboxes in it since I cant give them name because they are in a template.

Answer 1

If you have access to the templatedparent (SelectedItem, FindVisualParent etc.) you can do this if you apply Names to the TextBoxes. Example if ControlTemplate is for ComboBoxItem.

private void AddUser_Click(object sender, RoutedEventArgs e)
{
    ComboBoxItem comboBoxItem = GetVisualParent<ComboBoxItem>(button);
    TextBox textBox = comboBoxItem.Template.FindName("numberTextBox", comboBoxItem) as TextBox;
    //...
}

Another way to get the TextBoxes within the ControlTemplate would be to use the Visual Tree. Something like this

private void AddUser_Click(object sender, RoutedEventArgs e)
{
    Button button = sender as Button;
    Grid parentGrid = GetVisualParent<Grid>(button);
    List<TextBox> textBoxes = GetVisualChildCollection<TextBox>(parentGrid);
    foreach (TextBox textBox in textBoxes)
    {
        if (textBox.Tag == "Number")
        {
            // Do something..
        }
        else if (textBox.Tag == "Login")
        {
            // Do something..
        }
        else if (textBox.Tag == "Password")
        {
            // Do something..
        }
    }
}

And an implementation of GetVisualParent and GetVisualChildCollection

public static T GetVisualParent<T>(object childObject) where T : Visual
{
    DependencyObject child = childObject as DependencyObject;
    // iteratively traverse the visual tree
    while ((child != null) && !(child is T))
    {
        child = VisualTreeHelper.GetParent(child);
    }
    return child as T;
}

public static List<T> GetVisualChildCollection<T>(object parent) where T : Visual
{
    List<T> visualCollection = new List<T>();
    GetVisualChildCollection(parent as DependencyObject, visualCollection);
    return visualCollection;
}
private static void GetVisualChildCollection<T>(DependencyObject parent, List<T> visualCollection) where T : Visual
{
    int count = VisualTreeHelper.GetChildrenCount(parent);
    for (int i = 0; i < count; i++)
    {
        DependencyObject child = VisualTreeHelper.GetChild(parent, i);
        if (child is T)
        {
            visualCollection.Add(child as T);
        }
        else if (child != null)
        {
            GetVisualChildCollection(child, visualCollection);
        }
    }
}