XAML- creating an instance of a class

问题

I am trying to create an instance of a C# class from within the XAML markup of my application.

I am trying to use the instance of the C# class inside a <StackPanel></StackPanel> tag, inside a <TabItem></TabItem> tag that I have nested in the <TabControl></TabControl> tag where I have declared the namespace that the C# class belongs to:

<TabControl xmlns:agent="RAgent">
    <TabItem Header="R">
        <StackPanel>
            ...
        </StackPanel>
    </TabItem>
    <TabItem Header = "BClass">
        <StackPanel>
            <agent:BClass />
        </StackPanel>
    </TabItem>
</TabControl>

The C# class BClass is defined with:

namespace RAgent{
    public partial class BClass : UserControl{
        public BClass(){
            ...
        }
        ...
    }
}

I know that the C# code compiles and runs correctly, as I have previously run this separate to the rest of the application. However, when I currently try to build my code, I get a compile error in the XAML, on the line:

<agent:BClass />

which says:

The name "BClass" does not exist in the namespace "RAgent"

But BClass clearly does exist in the namespace RAgent, as I have declared the namespace at the top of the BClass.cs file with namespace RAgent{...

What am I doing wrong here? Am I trying to instantiate BClass incorrectly from within the XAML file? How should I do this?

Edit

Ok, so I've edited my .xaml file a bit based on the answer at How to create instance of class in XAML?, and on other bits of information I've picked up from various places.

I've added the line:

xmlns:local="clr-namespace:RAgent">

to the top of the file, and then removing the use of xmlns in the <TabControl> tag, and trying to create an instance of the class through local:

<TabControl>
    ...
    <TabItem Header="BClass">
        <StackPanel>
            <local:BClass x:Name="BClass" />
        </StackPanel>
    </TabItem>
</TabControl>

However, I now get a compile error on the line where I'm trying to instantiate the BClass:

<local:BClass x:Name="BClass" />

which says:

A value of type 'BClass' cannot be added to a collection or dictionary of type 'UIElementCollection'.

I tried removing the <StackPanel></StackPanel> tags, and although this removed the above compile error, it left me with one that says:

The name "BClass" does not exist in the namespace "clr-namespace:RAgent"- which it clearly does, as shown by the definition of BClass...

Anyone know how I can resolve this?

回答1:

I suggest you creating the TabControlin your MainApp and then each TabItemas a UserControl in your project. Then, you can easily instantiate your classes in the corresponding tab by doing <local:BClass x:Name="BClass"/>

Check Tabs in different XAML views and How to create and use an instance of a class in XAML for a better understanding

来源：https://stackoverflow.com/questions/37047773/xaml-creating-an-instance-of-a-class

标签

wpf

xaml

build-error