FindName(String name)==>It returns a null value...

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C#

private void Button1_Click(object sender, RoutedEventArgs e)
{
    TextBlock Var_TextBox = new TextBlock();
    Var_TextBox.Name = "TextBlock1";
    StackPanel_LayoutRoot.Children.Add(Var_TextBox);
}

private void Button2_Click(object sender, RoutedEventArgs e)
{
    object Var_TextBlock = FindName("TextBlock1");
}

Var_TextBlock=null

It returns a null value...؟

Posted 5-Jun-12 8:50am

Member 3232874

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Comments

Sergey Alexandrovich Kryukov 5-Jun-12 15:23pm

Is it System.Windows.FrameworkTemplate.FindName, System.Windows.FrameworkElement.FindName or something else? you should provide sufficient detail when asking question, not making us to do guesswork.
--SA

Sergey Alexandrovich Kryukov 5-Jun-12 15:24pm

What could be the sense of this horrific code? Why would you do that?
--SA

Sergey Alexandrovich Kryukov 5-Jun-12 15:28pm

Are you sure that: you call the method with the UIElement containing this StackPanel_LayoutRoot? Are you sure first method is called first, before the second one?
The code sample is not complete...
--SA

3 solutions

Solution 2

As I say, this code sample is not complete to give a final answer. To get one idea on this matter, please see:
http://stackoverflow.com/questions/2285491/wpf-findname-returns-null-when-it-should-not[^].

—SA

Posted 5-Jun-12 9:30am

Sergey Alexandrovich Kryukov

Comments

Clifford Nelson 5-Jun-12 19:39pm

The problem was that the name had never been registered, therefore could not find the name, see my solution.

Solution 1

I believe you are using the System.Windows.FrameworkElement.FindName() method. To do so, you should be calling it like so:

C#

StackPanel_LayoutRoot.FindName("TextBlock1");

Here is the MSDN link to how to use this method:

http://msdn.microsoft.com/en-us/library/system.windows.frameworkelement.findname.aspx[^]

Posted 5-Jun-12 9:27am

Tim Corey

v2

Comments

Clifford Nelson 5-Jun-12 19:39pm

The problem was that the name had never been registered, therefore could not find the name, see my solution.

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Clifford Nelson · Accepted Answer · 2012-06-05T09:32:00

Need to add a RegisterName call:

RegisterName("TextBlock1", Var_TextBox);

FindName operates within the current element's namescope. Any additions to the element tree after initial loading and processing must call the appropriate implementation of RegisterName for the class that defines the XAML namescope.
Otherwise, the added object cannot be referenced by name through methods such as FindName. Merely setting a Name property (or x:Name Attribute) does not register that name into any XAML namescope. Adding a named element to an element tree that has a XAML namescope also does not register the name to the XAML namescope.
The most common scenario for application developers is that you will use RegisterName to register names into the XAML namescope on the current root of the page.

FindName(String name)==>It returns a null value...

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