- 1 year ago
Can't change textbox text XAML, C++/CX: Undeclared Identifier
If you're encountering an "undeclared identifier" error when trying to change the text of a TextBox in XAML using C++/CX, it means that the compiler cannot find the identifier for the TextBox control. Here's a possible solution:
Ensure that you have the correct XAML namespace declaration at the top of your XAML file. It should include the necessary definitions for the TextBox control. For example:
xml<Page
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:YourAppNamespace"
...
>
Check that the TextBox control has a unique
x:Name
attribute defined in your XAML file. This attribute is used to generate the identifier that you can reference in your C++/CX code-behind file. For example:xml<TextBox x:Name="myTextBox" />
In your C++/CX code-behind file, make sure to include the appropriate header file for the XAML controls. The header file typically matches the name of your XAML file with a ".h" extension. For example, if your XAML file is named "MainPage.xaml," the code-behind file would be "MainPage.xaml.h".
Inside your C++/CX code-behind file, access the TextBox control by using the
this->
syntax followed by thex:Name
you defined in your XAML file. Then, you can modify theText
property to change the text. For example:cpp// MainPage.xaml.h
#pragma once
...
namespace YourAppNamespace
{
public ref class MainPage sealed
{
public:
MainPage();
...
};
}
// MainPage.xaml.cpp
#include "MainPage.xaml.h"
...
using namespace Windows::UI::Xaml::Controls;
...
MainPage::MainPage()
{
InitializeComponent();
myTextBox->Text = "New text"; // Change the text of the TextBox
}
By following these steps, you should be able to modify the text of a TextBox control in XAML using C++/CX without encountering an "undeclared identifier" error.