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，我得到一些非常奇怪的行为。例如，当我检查两个CheckBoxes时，它告诉我有2选择，但是如果我在DataGrid中向上或向下滚动，则数字会更改。如果我回滚到初始位置，则返回到2选择。听起来很奇怪，当我滚动框时，它似乎被称为检查/未检查事件...非常奇怪...

我将以下定义在我的代码的顶部：

  private DataSet MyDataSet; 
 int selected_count = 0; 
  

然后，我的方法中有以下代码将信息加载到DataSet中：

  MyDataSet = new DataSet（）; 
 DataTable tempDataTable = new DataTable（）; 
 MyDataSet.Tables.Add（tempDataTable）; 
 
 DataColumn tempCol = new DataColumn（Checked，typeof（bool））; 
 tempDataTable.Columns.Add（tempCol）; （int i = 0; i <50; i ++）
 {
 DataRow tempRow = tempDataTable.NewRow（）; 
 
 
 tempDataTable.Rows.Add（tempRow）; 
 tempRow [Checked] = false; 
} 
 
 MyList.ItemsSource = MyDataSet.Tables [0] .DefaultView; 
  

我将IsChecked属性绑定到使用以下XAML命名为Checked的DataColumn：

 < dtgrd：DataGrid x：Name =MyListAutoGenerateColumns =FalseCanUserAddRows =FalseCanUserResizeRows =FalseHeadersVisibility = ColumnSelectionUnit =FullRowHorizo​​ntalGridLinesBrush =＃FF688CAFVerticalGridLinesBrush =＃FF688CAF> 
< dtgrd：DataGrid.Columns> 
< dtgrd：DataGridTemplateColumn x：Name =CheckColCanUserSort =TrueCanUserResize =False> 
< dtgrd：DataGridTemplateColumn.CellTemplate> 
< DataTemplate> 
< CheckBox Name =MyCheckBoxIsChecked ={Binding Checked}Horizo​​ntalAlignment =CenterVerticalAlignment =CenterChecked =MyCheckBox_CheckedUnchecked =MyCheckBox_Unchecked/> 
< / DataTemplate> 
< / dtgrd：DataGridTemplateColumn.CellTemplate> 
< / dtgrd：DataGridTemplateColumn> 
< / dtgrd：DataGrid.Columns> 
< / dtgrd：DataGrid> 
  

然后，我通过检查/取消选中其中一个复选框来调用以下事件： p>

  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; 
} 
  

我也尝试过其他的东西，但是会收到不同的错误。例如，我从XAML代码中删除了Binding，并尝试使用以下Checked / Uncheck事件以编程方式进行设置：

  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，但在滚动的时候，实际的检查会移动到不同的项目。

我真的不知道发生了什么，但这是非常令人沮丧的！任何帮助将是非常感谢！

解决方案

您正在进入物品容器回收。请参阅 http：// blogs。 msdn.com/b/vinsibal/archive/2008/05/14/recycling-that-item-container.aspx 。 WPF正在滚动时重新使用行对象，并且您看到已检查和未检查事件在绑定到另一行时触发。

如果您想坚持使用当前的解决方案，您可以通过添加 VirtualizingStackPanel.VirtualizationMode =Standard来禁用项目容器回收
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。

更好的设计可能是从底层数据模型获取数据，而不是依赖于UI事件。尝试处理 DataTable.ColumnChanged 事件数据表。

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...

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

private DataSet MyDataSet;
int selected_count = 0;

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;

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>

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";
}

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";
}

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.

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

解决方案

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.

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".

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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