C#使用动态文本框/按钮/网格删除行

发布时间：2020-12-15 22:15:44 所属栏目：百科来源：网络整理

导读：我已经测试了一些想法与动态文本框和按钮,添加项目到我的网格工作得很好,但如果我想删除它有一些错误,有时1行是空的,我的添加按钮消失或我的程序崩溃. 我错了什么或错过了什么？ C#代码： public MainWindow() { InitializeComponent(); } int Numberic = 0;

我已经测试了一些想法与动态文本框和按钮,添加项目到我的网格工作得很好,但如果我想删除它有一些错误,有时1行是空的,我的添加按钮消失或我的程序崩溃.

我错了什么或错过了什么？

C#代码：

public MainWindow()
    {
        InitializeComponent();
    }

    int Numberic = 0;
    private void NewButton_Click(object sender,RoutedEventArgs e)
    {
        #region Row and Numberic
        Numberic++;
        RowDefinition ROW = new RowDefinition();
        GridLength Height = new GridLength(59);
        ROW.Height = Height;

        MainGrid.RowDefinitions.Add(ROW);
        #endregion

        #region Set new Button Location
        int ButtonLocation = Grid.GetRow(NewButton);
        Grid.SetRow(NewButton,ButtonLocation + 1);
        #endregion

        #region Create TextBox
        TextBox CreateTextBox = new TextBox();
        CreateTextBox.Name = "NewTextBox_" + Numberic;
        CreateTextBox.Width = 438;
        CreateTextBox.Height = 35;
        CreateTextBox.Margin = new Thickness(53,12,0);
        CreateTextBox.HorizontalAlignment = HorizontalAlignment.Left;
        CreateTextBox.VerticalAlignment = VerticalAlignment.Top;

        CreateTextBox.FontSize = 15;
        CreateTextBox.HorizontalContentAlignment = HorizontalAlignment.Left;
        CreateTextBox.VerticalContentAlignment = VerticalAlignment.Center;

        MainGrid.Children.Add(CreateTextBox);
        Grid.SetRow(CreateTextBox,ButtonLocation);
        #endregion

        #region Create Button
        Button CreateButton = new Button();
        CreateButton.Name = "NewButton_" + Numberic;
        CreateButton.Width = 35;
        CreateButton.Height = 35;
        CreateButton.Margin = new Thickness(12,0);
        CreateButton.HorizontalAlignment = HorizontalAlignment.Left;
        CreateButton.VerticalAlignment = VerticalAlignment.Top;

        CreateButton.Content = "-";
        CreateButton.FontSize = 20;
        CreateButton.FontWeight = FontWeights.Bold;
        BrushConverter BC = new BrushConverter();
        CreateButton.Background = (Brush)BC.ConvertFrom("#FFDB0000");
        CreateButton.Foreground = Brushes.White;
        CreateButton.BorderBrush = Brushes.Transparent;

        CreateButton.Click += new RoutedEventHandler(Delete_OnClick);

        MainGrid.Children.Add(CreateButton);
        Grid.SetRow(CreateButton,ButtonLocation);
        #endregion
    }

    private void Delete_OnClick(object sender,RoutedEventArgs e)
    {
        Button SelectedButton = (Button)sender;
        int SelectedRow = Grid.GetRow(SelectedButton);

        string[] Number = SelectedButton.Name.Split('_');
        string TextBoxName = "NewTextBox" + "_" + Number[1];
        TextBox SelectedTextbox = (TextBox)LogicalTreeHelper.FindLogicalNode(MainGrid,TextBoxName);

        MainGrid.Children.Remove(SelectedTextbox);
        MainGrid.Children.Remove(SelectedButton);

        //Numberic--;
        MainGrid.RowDefinitions.RemoveAt(SelectedRow);
    }

XAML代码：

<Grid Name="MainGrid" ShowGridLines="True" OpacityMask="Black" Background="#FFEDEDED">
    <Grid.RowDefinitions>
        <RowDefinition Height="59" />
    </Grid.RowDefinitions>
    <Button Content="+" Height="35" HorizontalAlignment="Left" Margin="12,0" Name="NewButton" VerticalAlignment="Top" Width="35" BorderBrush="{x:Null}" Foreground="White" Background="#FF727272" FontWeight="Bold" FontSize="20" Click="NewButton_Click" />
</Grid>

谢谢,
Tkay

解决方法

当项目数量可以更改时,WPF的ItemsControl是在视图中显示项目的正确方法.

许多控件继承自ItemsControl,如ComboBox本身,或DataGrid,或ListBox ……但在这个例子中,我将直接使用ItemsControl,因为你要做的事情不需要任何额外的功能.

首先,XAML：

<Grid Name="MainGrid" OpacityMask="Black" Background="#FFEDEDED">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>

        <ItemsControl x:Name="MyItemsControl">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <Button Content="-" Height="35" HorizontalAlignment="Left" Margin="12,0" Name="NewButton" VerticalAlignment="Top" Width="35" BorderBrush="{x:Null}" Foreground="White" Background="#FFDB0000" FontWeight="Bold" FontSize="20" Click="Delete_OnClick" />
                        <TextBox Width="438" Height="35" Margin="6,0" HorizontalAlignment="Left" VerticalAlignment="Top" FontSize="15" HorizontalContentAlignment="Left" VerticalContentAlignment="Center" />
                    </StackPanel>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>

        <Button Grid.Row="1" Content="+" Height="35" HorizontalAlignment="Left" Margin="12,0" Name="NewButton" VerticalAlignment="Top" Width="35" BorderBrush="{x:Null}" Foreground="White" Background="#FF727272" FontWeight="Bold" FontSize="20" Click="NewButton_Click" />
    </Grid>

我已将“ – ”按钮和TextBox的定义放在ItemTemplate中.对于我们添加到其中的每个项目,ItemsControl将重用此模板.

现在,代码隐藏：

public partial class MainWindow : Window
{
    int Numberic = 0;

    private void NewButton_Click(object sender,RoutedEventArgs e)
    {
        var item = new Item();
        item.Id = ++Numberic;
        MyItemsControl.Items.Add(item);
    }

    private void Delete_OnClick(object sender,RoutedEventArgs e)
    {
        Button SelectedButton = (Button)sender;
        var item = SelectedButton.DataContext;
        MyItemsControl.Items.Remove(item);
    }
}

正如您所看到的,这比您之前的方法更简单,更清晰.大多数逻辑由ItemsControl处理,您只需要向其中添加和删除项目.

我已经为ItemsControl的项目使用了自定义类(Item),但它可以是你想要的任何东西.在这种情况下,Item的定义只是：

public class Item
{
    public int Id { get; set; }
}

检查在Delete_OnClick方法中我是否使用DataContext属性来检索当前的Item实例.

这是因为当你将一个对象添加到ItemsControl时,它会使用它的可视化表示(我们在模板中定义,在这种情况下)创建相应的“可视项目”,并将添加的对象指定为此“可视项目”的DataContext “和控制.这样你就可以直接创建Bindings到它的属性等.

（编辑：李大同）

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