在WPF中将TabItem转换为UserControl [英] Casting a TabItem to UserControl in WPF

问题描述

我在主屏幕上有一个Tab控件。它有不同的选项卡项。例如：

 < TabControl Name =mainTabPadding =0Margin =70,80,350,49> ; 
<！ -  Left，Top，Right，Bottom  - > 
< TabItem GotFocus =TabItem_Animals_GotFocus> 
< TabItem.Header> 
动物
< /TabItem.Header> 
< ContentControl Margin =10> 
< Frame Name =animalFrameSource =AnimalWorkSpaceView.xaml>< / Frame> 
< / ContentControl> 
< / TabItem> 
< TabItem GotFocus =TabItem_Calfs_GotFocus> 
< TabItem.Header> 
 Calfs 
< /TabItem.Header> 
< ContentControl Margin =10> 
< Frame Name =calfFrameSource =CalfWorkSpaceView.xaml>< / Frame> 
< / ContentControl> 
< / TabItem> 
  

等等。

以下是标签的设计时预览：

每个选项卡项控件都继承自 WorkSpaceViewControl （一个派生自 UserControl ）

正如你所看到的，有一个刷新按钮来刷新控件（重载 datagrid

按钮的代码是：

  private void buttonRefresh_Click（object sender，RoutedEventArgs e）
 {
 // var x = mainTab.SelectedItem as TabItem; 
 //MessageBox.Show(x.Header.ToString());//显示标题
 // var t = x.Content as TextBlock; 
 //MessageBox.Show (t.Text）; 
 
 var ctrl = mainTab.SelectedItem as TabItem; 
 
 var myCtrl1 =（WorkSpaceViewControl）ctrl; 
 myCtrl1.Refresh（）; 
} 
  

Refresh（）是WorkSpaceViewControl中的一个虚拟方法

每当我调用该代码时，它在转换时会出现错误。我已经尝试了很多方法来投射：隐式，显式（，你可以看到一些尝试在上面的注释代码以及）。

这里是显式转换的代码我试图实现（但失败）：

  public static explicit operator WorkSpaceViewControl（TabItem v）
 {
 if（v.Content是WorkSpaceViewControl）
 {
 return v.Content as WorkSpaceViewControl; 
} 
 else 
 {
 throw new InvalidCastException（）; 
} 
} 
  

它总是通过接受else条件：

我可以投放它吗？如何？非常感谢您回答。

UPDATE

抽象类是： p>

  public abstract class WorkSpaceViewControl：UserControl 
 {
 public WorkSpaceViewControl（）
 {
 InitializeComponent（）; 
} 
 
 private void InitializeComponent（）
 {
 // 
} 
 
 #region继承方法
 public virtual void GetSelectedEntry（）
 {
 
} 
 
 public virtual void Refresh（）
 {
 $ b b 
 
 public static explicit operator WorkSpaceViewControl（TabItem v）
 {
 if（v.Content是WorkSpaceViewControl）
 {
 return v.Content as WorkSpaceViewControl; 
} 
 else 
 {
 throw new InvalidCastException（）; 
} 
} 
 
 
 b $ b #endregion 
} 
  

解决方案

有一个接口：

  interface IWorkSpaceViewControl 
 {
 void GetSelectedEntry（）; 
 void Refresh （）; 
 
 bool CanSave {get;} 
 void Save（）; 
} 
  

和一个userControl：

 < UserControl x：Class =WpfApplication9.DemoUserControl 
 xmlns =http://schemas.microsoft.com/winfx/2006/xaml/presentation
 xmlns：x =http://schemas.microsoft.com/winfx/2006/xaml 
 xmlns：mc =http://schemas.openxmlformats.org/markup-compatibility/2006
 xmlns：d =http://schemas.microsoft.com/expression/blend/2008 
 mc：Ignorable =d
d：DesignHeight =300d：DesignWidth =300> 
< Grid> 
< Button Name =btnChangeCanSaveClick =btnChangeCanSave_Click>更改CanSave< / Button> 
< / Grid> 
< / UserControl> 
  

代码背后：

  public partial class DemoUserControl：UserControl，IWorkSpaceViewControl 
 {
 private bool canSave; 
 
 public DemoUserControl（）
 {
 InitializeComponent（）; 
} 
 
 public void GetSelectedEntry（）
 {
 //您的实现
} 
 
 public void Refresh（）
 {
 //您的实现
 Debug.WriteLine（DemoUserControl Refresh（）executed）; 
} 
 
 
 public bool CanSave 
 {
 get {return canSave; } 
} 
 
 private void btnChangeCanSave_Click（object sender，RoutedEventArgs e）
 {
 canSave =！canSave; 
} 
 
 
 public void Save（）
 {
 Debug.WriteLine（DemoUserControl Save（）executed）; 
} 
} 
  

和一个MainWindow：

 < Window xmlns：WpfApplication9 =clr-namespace：WpfApplication9x：Class =WpfApplication9.MainWindow
 xmlns =http： /schemas.microsoft.com/winfx/2006/xaml/presentation
 xmlns：x =http://schemas.microsoft.com/winfx/2006/xaml
标题=MainWindow高度=350Width =525> 
< Window.CommandBindings> 
< CommandBinding Command =ApplicationCommands.SaveCanExecute =SaveCommand_CanExecuteExecuted =SaveCommand_Executed/> 
< /Window.CommandBindings> 
< Grid> 
< Grid.RowDefinitions> 
< RowDefinition Height =auto/> 
< RowDefinition /> 
< /Grid.RowDefinitions> 
< WrapPanel> 
< Button Name =btnRefreshClick =btnRefresh_Click> Refresh< / Button> 
< Button Command =ApplicationCommands.Save> Save< / Button> 
< / WrapPanel> 
< TabControl Name =tabControlGrid.Row =1> 
< TabItem> 
< TabItem.Header>动物< /TabItem.Header> 
< WpfApplication9：DemoUserControl Margin =10/> 
< / TabItem> 
< / TabControl> 
< / Grid> 
< / Window> 
  

代码背后：

  public partial MainWindow：Window 
 {
 public MainWindow（）
 {
 InitializeComponent（）; 
 
} 
 
 private void btnRefresh_Click（object sender，RoutedEventArgs e）
 {
 IWorkSpaceViewControl control = tabControl.SelectedContent as IWorkSpaceViewControl; 
 control.Refresh（）; 
} 
 
 private void SaveCommand_CanExecute（object sender，CanExecuteRoutedEventArgs e）
 {
 if（tabControl！= null）
 {
 CanExecute =（（IWorkSpaceViewControl）tabControl.SelectedContent）.CanSave; 
} 
} 
 
 private void SaveCommand_Executed（object sender，ExecutedRoutedEventArgs e）
 {
（（IWorkSpaceViewControl）tabControl.SelectedContent）.Save 
} 
} 
  

I have a Tab Control on my main screen. It has different tab items. For example:

<TabControl Name="mainTab"  Padding="0" Margin="70,80,350,49">
            <!--Left,Top,Right, Bottom-->
            <TabItem GotFocus="TabItem_Animals_GotFocus">
                <TabItem.Header>
                    Animals
                </TabItem.Header>
                <ContentControl Margin="10">
                    <Frame Name="animalFrame" Source="AnimalWorkSpaceView.xaml"></Frame>
                </ContentControl>
            </TabItem>
            <TabItem GotFocus="TabItem_Calfs_GotFocus">
                <TabItem.Header>
                    Calfs
                </TabItem.Header>
                <ContentControl Margin="10">
                    <Frame Name="calfFrame" Source="CalfWorkSpaceView.xaml"></Frame>
                </ContentControl>
            </TabItem>

and so on..

Here is design-time preview of tabs:

Every tab item control is inherited from WorkSpaceViewControl (an abstract class derived from UserControl)

As you can see there is a Refresh button to refresh the control (Reload it's datagrid members)

The code behind Refresh button is:

private void buttonRefresh_Click(object sender, RoutedEventArgs e)
        {
        //var x = mainTab.SelectedItem as TabItem;
        //MessageBox.Show(x.Header.ToString());//shows the header
        //var t = x.Content as TextBlock;
        //MessageBox.Show(t.Text);

        var ctrl = mainTab.SelectedItem as TabItem;

        var myCtrl1 = (WorkSpaceViewControl)ctrl;
        myCtrl1.Refresh();
}

Refresh() is a virtual method in WorkSpaceViewControl class and overridden in subsequent classes.

Whenever I call that code, it gives me error on casting. I have tried a lot of methods of casting: Implicit, explicit (as you can see some tries in commented code above as well).

Here is code of Explicit casting I tried to implement (but failed):

public static explicit operator WorkSpaceViewControl(TabItem v)
        {
            if (v.Content is WorkSpaceViewControl)
            {
                return v.Content as WorkSpaceViewControl;
            }
            else
            {
                throw new InvalidCastException();
            }
        }

It always throws me Invalid Cast by taking into else condition:

Can I cast it and How? Thanks for answering it.

UPDATE

The abstract class is:

public abstract class WorkSpaceViewControl : UserControl
{
    public WorkSpaceViewControl()
    {
        InitializeComponent();
    }

    private void InitializeComponent()
    {
        //
    }

    #region Inheritance Methods (for sub classes
    public virtual void GetSelectedEntry()
    {

    }

    public virtual void Refresh()
    {

    }

    public static explicit operator WorkSpaceViewControl(TabItem v)
    {
        if (v.Content is WorkSpaceViewControl)
        {
            return v.Content as WorkSpaceViewControl;
        }
        else
        {
            throw new InvalidCastException();
        }
    }



    #endregion
}

解决方案

You have an interface:

interface IWorkSpaceViewControl
{
    void GetSelectedEntry();
    void Refresh();

    bool CanSave { get; }
    void Save();
}

And a userControl:

<UserControl x:Class="WpfApplication9.DemoUserControl"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <Button Name="btnChangeCanSave" Click="btnChangeCanSave_Click">Change CanSave</Button>
    </Grid>
</UserControl>

Code Behind:

public partial class DemoUserControl : UserControl, IWorkSpaceViewControl
{
    private bool canSave;

    public DemoUserControl()
    {
        InitializeComponent();
    }

    public void GetSelectedEntry()
    {
        // Your implementation
    }

    public void Refresh()
    {
        // Your Implementation
        Debug.WriteLine("DemoUserControl Refresh() executed");
    }


    public bool CanSave
    {
        get { return canSave; }
    }

    private void btnChangeCanSave_Click(object sender, RoutedEventArgs e)
    {
        canSave = !canSave;
    }


    public void Save()
    {
        Debug.WriteLine("DemoUserControl Save() executed");
    }
}

and a MainWindow:

<Window xmlns:WpfApplication9="clr-namespace:WpfApplication9"  x:Class="WpfApplication9.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Window.CommandBindings>
        <CommandBinding Command="ApplicationCommands.Save" CanExecute="SaveCommand_CanExecute" Executed="SaveCommand_Executed"/>
    </Window.CommandBindings>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="auto"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <WrapPanel>
            <Button Name="btnRefresh" Click="btnRefresh_Click">Refresh</Button>
            <Button Command="ApplicationCommands.Save">Save</Button>
        </WrapPanel>
        <TabControl Name="tabControl" Grid.Row="1">
            <TabItem>
                <TabItem.Header>Animals</TabItem.Header>
                <WpfApplication9:DemoUserControl Margin="10" />
            </TabItem>
        </TabControl>
    </Grid>
</Window>

with Code Behind:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

    }

    private void btnRefresh_Click(object sender, RoutedEventArgs e)
    {
        IWorkSpaceViewControl control = tabControl.SelectedContent as IWorkSpaceViewControl;
        control.Refresh();
    }

    private void SaveCommand_CanExecute(object sender, CanExecuteRoutedEventArgs e)
    {
        if (tabControl != null)
        {
            e.CanExecute = ((IWorkSpaceViewControl)tabControl.SelectedContent).CanSave;
        }
    }

    private void SaveCommand_Executed(object sender, ExecutedRoutedEventArgs e)
    {
        ((IWorkSpaceViewControl)tabControl.SelectedContent).Save();
    }
}

这篇关于在WPF中将TabItem转换为UserControl的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！