Question

I have a tabcontrol with 9 tabitems in it. Each tab has as series of TextBoxes for the user to enter data. At the bottom is a clear button, hooked up to this method:

public void ClearTextBoxes()
    {
        ChildControls ccChildren = new ChildControls();

        foreach (object o in ccChildren.GetChildren(rvraDockPanel, 2))
        {
            if (o.GetType() == typeof(WatermarkTextBox) || o.GetType() == typeof(DateBox) ||
                o.GetType() == typeof(DigitBox) || o.GetType() == typeof(PhoneBox))
            {
                WatermarkTextBox water = (WatermarkTextBox)o;
                water.Text = "";
            }
            else if (o.GetType() == typeof(ComboBox))
            {
                ComboBox combo = (ComboBox)o;
                combo.SelectedIndex = -1;
            }
            else if (o.GetType() == typeof(CheckBox))
            {
                CheckBox check = (CheckBox)o;
                check.IsChecked = false;
            }
        }
    }

This works perfectly fine, however I also have a MenuItem that allows the user to ClearAll tabs. Right now the clear button only clears what’s on the currently selected tab, and leaves everything else alone. My thought on how to do this was to iterate through the tabitems with this loop:

        for (int i = 0; i < 10; i++ )
        {
            tabSelection.SelectedIndex = i;
            clearButton_Click(null, null);
        }

It will flip through all the tabs, but won’t clear anything. I have tried using Automation instead, with the same result. It just won’t seem to clear anything.

ChildControls class:

class ChildControls
{
private List<object> listChildren;

public List<object> GetChildren(Visual p_vParent, int p_nLevel)
{
    if (p_vParent == null)
    {
        throw new ArgumentNullException("Element {0} is null!", p_vParent.ToString());
    }

    this.listChildren = new List<object>();

    this.GetChildControls(p_vParent, p_nLevel);

    return this.listChildren;

}

private void GetChildControls(Visual p_vParent, int p_nLevel)
{
    int nChildCount = VisualTreeHelper.GetChildrenCount(p_vParent);

    for (int i = 0; i <= nChildCount - 1; i++)
    {
        Visual v = (Visual)VisualTreeHelper.GetChild(p_vParent, i);

        listChildren.Add((object)v);

        if (VisualTreeHelper.GetChildrenCount(v) > 0)
        {
            GetChildControls(v, p_nLevel + 1);
        }
    }
}

}

Answer 1

To get your code working you need to add the following line to your cleanup method:

        tabControl.SelectedIndex = i;
-->        UpdateLayout();
        Button_Click(null, null);

The UpdateLayout method takes care that the TabItem is drawn and the VisualTree is available afterwards.

Generally this approach isn’t nice and if you have a real Application with Business data behind I’d recommend you have a look at databinding/MVVM. The approach shouldn’t be to reset your controls in the view, but to reset your bound business data in the background.