WPF 工具包 DataGrid 复选框问题 [英] WPF Toolkit DataGrid Checkbox Issues

问题描述

我真的希望有人能在这里帮助我.我的程序中有一个 DataGrid，它有一个复选框列.DataGrid 的 ItemsSource 是以编程方式加载的 DataSet.当我在 DataGrid 中选择几个项目然后滚动它时，我得到了一些非常奇怪的行为.例如，当我检查两个 CheckBox 时，它告诉我我选择了2"，但是如果我在 DataGrid 中向上或向下滚动，数字会发生变化.如果我滚动回初始位置，它会返回到2 selected".听起来很奇怪，当我滚动框时，它似乎正在调用 Checked/Unchecked 事件......非常奇怪......

I'm really hoping someone can help me out here. I have a DataGrid in my program that has a checkbox column. The ItemsSource for the DataGrid is a DataSet loaded programmatically. When I select a couple of items in the DataGrid and then scroll it, I get some very odd behavior. For example, when I check two of the CheckBoxes, it tells me that I have "2 selected", but then if I scroll up or down in the DataGrid, the number changes. If I scroll back to the initial position it goes back to the "2 selected". As odd as it sounds, it seems like it's calling the Checked/Unchecked events when I scroll the box...very odd...

我在代码顶部定义了以下内容:

I have the following defined at the top of my code:

private DataSet MyDataSet;
int selected_count = 0;

然后我在我的方法中有以下代码将信息加载到数据集中:

Then I have the following code in my method to load the information into the DataSet:

MyDataSet = new DataSet();
DataTable tempDataTable = new DataTable();
MyDataSet.Tables.Add(tempDataTable);

DataColumn tempCol = new DataColumn("Checked", typeof(bool));
tempDataTable.Columns.Add(tempCol);

for (int i = 0; i < 50; i++)
{
    DataRow tempRow = tempDataTable.NewRow();
    tempDataTable.Rows.Add(tempRow);
    tempRow["Checked"] = false;
}

MyList.ItemsSource = MyDataSet.Tables[0].DefaultView;

我使用以下 XAML 将 IsChecked 属性绑定到名为Checked"的 DataColumn:

I have the IsChecked property binded to the DataColumn named "Checked" using the following XAML:

<dtgrd:DataGrid x:Name="MyList" AutoGenerateColumns="False" CanUserAddRows="False" CanUserResizeRows="False" HeadersVisibility="Column" SelectionUnit="FullRow" HorizontalGridLinesBrush="#FF688CAF" VerticalGridLinesBrush="#FF688CAF">
    <dtgrd:DataGrid.Columns>
        <dtgrd:DataGridTemplateColumn x:Name="CheckCol" CanUserSort="True" CanUserResize="False">
            <dtgrd:DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <CheckBox Name="MyCheckBox" IsChecked="{Binding Checked}" HorizontalAlignment="Center" VerticalAlignment="Center" Checked="MyCheckBox_Checked" Unchecked="MyCheckBox_Unchecked" />
                </DataTemplate>
            </dtgrd:DataGridTemplateColumn.CellTemplate>
        </dtgrd:DataGridTemplateColumn>
    </dtgrd:DataGrid.Columns>
</dtgrd:DataGrid>

然后，我通过选中/取消选中其中一个复选框来调用以下事件:

Then, I have the following events that are called by checking/unchecking one of the checkboxes:

private void MyCheckBox_Checked(object sender, RoutedEventArgs e)
{
    selected_count++;
    TxtSelectedCount.Text = "" + selected_count + " selected";
}

private void MyCheckBox_Unchecked(object sender, RoutedEventArgs e)
{
    selected_count--;
    TxtSelectedCount.Text = "" + selected_count + " selected";
}

我也尝试过其他东西，但遇到了不同的错误.例如，我从 XAML 代码中删除了 Binding 并尝试使用以下 Checked/Uncheck 事件以编程方式设置它:

I have also tried other things, but get different bugs. For example, I removed the Binding from the XAML code and tried to set it programmatically using the following Checked/Uncheck events:

private void MyCheckBox_Checked(object sender, RoutedEventArgs e)
{
    DataRow tempRow = MyDataSet.Tables[0].Rows[MyList.Items.IndexOf(MyList.SelectedItems[0])];
    tempRow["Checked"] = true;

    selected_count++;
    TxtSelectedCount.Text = "" + selected_count + " selected";
}

private void MyCheckBox_Unchecked(object sender, RoutedEventArgs e)
{
    DataRow tempRow = MyDataSet.Tables[0].Rows[MyList.Items.IndexOf(MyList.SelectedItems[0])];
    tempRow["Checked"] = false;

    selected_count--;
    TxtSelectedCount.Text = "" + selected_count + " selected";
}

当我使用该代码时，检查项目的数量保持不变，但实际检查在我滚动时移动到不同项目.

When I use that code, the number of checked items stays the same, but the actual checks move around to different items while I'm scrolling.

老实说，我不知道发生了什么，但这非常令人沮丧！任何帮助将不胜感激！

I honestly have no clue what's going on, but it's very frustrating! Any help would be GREATLY appreciated!

推荐答案

您遇到了物品容器回收问题.请参阅 http://blogs.msdn.com/b/vinsibal/archive/2008/05/14/recycling-that-item-container.aspx.WPF 在您滚动时重新使用行对象，您会看到 Checked 和 Unchecked 事件在它绑定到不同的行时触发.

You're running into item container recycling. See http://blogs.msdn.com/b/vinsibal/archive/2008/05/14/recycling-that-item-container.aspx. WPF is re-using the row objects as you scroll, and you're seeing the Checked and Unchecked events fire as it binds to a different row.

如果你想坚持你当前的解决方案，你可以禁用物品容器回收通过将 VirtualizingStackPanel.VirtualizationMode="Standard" 添加到您的 dtgrd:DataGrid 元素.您还可以通过添加 VirtualizingStackPanel.IsVirtualizing="False" 来完全禁用虚拟化.

If you want to stick with your current solution, you can just disable item container recycling by adding VirtualizingStackPanel.VirtualizationMode="Standard" to your dtgrd:DataGrid element. You could also disable virtualization entirely by adding VirtualizingStackPanel.IsVirtualizing="False".

更好的设计可能是从您的底层数据模型中获取数据，而不是依赖于 UI 事件.尝试处理 DataTable.ColumnChanged 事件数据表.

A better design might be to get that data from your underlying data model rather than relying on the UI events. Try handling the DataTable.ColumnChanged event on the DataTable.

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