将DataGrid列宽绑定到另一个DataGrid的两个列 [英] Bind DataGrid Column Width to Two Colums of Another DataGrid

问题描述

问题：如何将 StatName.Width 绑定到 Samp1.ActualWidth + Samp2.ActualWidth ？

子-问题：

为什么我的 WidthConverter 函数从未执行过（断点从未命中）？

Why are my WidthConverter functions never executed (breakpoints never hit)?

单个MultiBinding组件正确的< Binding ... 语法是什么？

What is the right <Binding ... syntax for the individual MultiBinding components?

我尝试过的操作

我认为我需要分配 DataGridTextColumn.Width 和 MultiBinding 和某些类型的转换器。

I think I need to assign the DataGridTextColumn.Width with MultiBinding and some type of converter.

我尝试过在线收集各种示例的解决方案。我似乎无法将所有内容放在一起。

I have tried putting together a solution from various examples online. I can't seem to pull it all together.

编辑

使用<绑定ElementName = Samp1 Path = ActualWidth />

1. 没有构建错误或警告。


2. 未命中 Convert 函数


3. 否输出中的相关消息

1. No build errors or warnings.
2. The Convert function is not hit
3. No relevant messages in Output

使用< Binding Source = {x：Reference Samp1} Path = ActualWidth />

1. 生成错误（仍然允许执行）：指定的强制转换无效。对于< MultiBinding> ...< / MultiBinding> 。


2. 转换在加载时被调用了三次。调整
   列 Samp1 的大小时不会调用它。


3. 每次执行转换：

1. Build error (that still allows execution): Specified cast is not valid. For <MultiBinding>...</MultiBinding>.
2. Convert is called three times when loading. It is not called when resizing column Samp1.
3. On each execution of Convert:

System.Windows.Data错误：5：BindingExpression生成的值不是对目标财产有效。值= 40 MultiBindingExpression：目标元素是 DataGridTextColumn（HashCode = 64879470）；目标属性为宽度（类型为 DataGridLength）

MultiBinding Attempt （xaml部分）

<Page.Resources>
    <local:WidthConverter x:Key="WidthConverter" />
</Page.Resources>

<StackPanel>

    <DataGrid IsReadOnly="True" HeadersVisibility="Column">
        <DataGrid.Columns>
            <DataGridTextColumn x:Name="Samp1" Binding="{Binding a}" Header="S1" />
            <DataGridTextColumn x:Name="Samp2" Binding="{Binding b}" Header="S2" />
            <DataGridTextColumn x:Name="Total" Binding="{Binding c}" Header="Tot" />
        </DataGrid.Columns>
        <local:MyGenericRecord a="5000" b="2500" c="7500" />
        <local:MyGenericRecord a="1000" b="1500" c="2500" />
    </DataGrid>

    <DataGrid IsReadOnly="True" HeadersVisibility="Column">
        <DataGrid.Columns>
            <DataGridTextColumn x:Name="StatName"  Binding="{Binding a}" Header="Stat">
                <DataGridTextColumn.Width>
                    <MultiBinding Converter="{StaticResource WidthConverter}">
                        <Binding ElementName="Samp1" Path="ActualWidth" />
                        <Binding ElementName="Samp2" Path="ActualWidth" />
                    </MultiBinding>
                </DataGridTextColumn.Width>
            </DataGridTextColumn>
            <DataGridTextColumn x:Name="StatValue" Binding="{Binding b}" Header="Val" Width="{Binding ElementName=Total, Path=ActualWidth}" />
        </DataGrid.Columns>
        <local:MyGenericRecord a="Min" b="2500" />
        <local:MyGenericRecord a="Max" b="7500" />
        <local:MyGenericRecord a="Average" b="5000" />
    </DataGrid>

</StackPanel>

多重绑定尝试（代码部分）

public class WidthConverter : IMultiValueConverter
{

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        double totalWidth = 0;

        foreach (DataGridLength Width in values)
            totalWidth += Width.Value;

        return totalWidth;
    }
    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        return null;
    }
}

推荐答案

代码最终将按预期执行以下操作：

The code finally executes as expected with the following:

• < Binding Source = {x：Reference Samp2} Path = ActualWidth />


• 返回新的DataGridLength（totalWidth）;

• <Binding Source="{x:Reference Samp2}" Path="ActualWidth" />
• return new DataGridLength(totalWidth);

转换器在加载时和调整 Samp1大小时会被调用或 Samp2 。列宽按预期保持同步。

The Converter gets called on load and when resizing Samp1 or Samp2. The column widths remain synchronized as expected.

<DataGridTextColumn x:Name="StatName"  Binding="{Binding a}" Header="Stat">
   <DataGridTextColumn.Width >
       <MultiBinding Converter="{StaticResource WidthConverter}">
           <Binding Source="{x:Reference Samp1}" Path="ActualWidth" />
           <Binding Source="{x:Reference Samp2}" Path="ActualWidth" />
       </MultiBinding>
   </DataGridTextColumn.Width>
</DataGridTextColumn>

Convert 函数需要返回 DataGridLength ，数据类型为 DataGridTextColumn.Width 。

The Convert function needed to return a DataGridLength, the data type of DataGridTextColumn.Width.

public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{

    double totalWidth = 0;

    foreach (double Width in values)
        totalWidth += Width;

    return new DataGridLength(totalWidth);
}

注意：该代码将按预期执行，无论错误指定的转换无效。

Note: The code executes as expected, regardless of the error Specified cast is not valid.

1. Visual Studio设计器强调整个标签< MultiBinding ...< / MultiBinding> 用青色表示。


2. 错误列表窗口报告错误指定的转换无效。


3. 虽然显示为错误，但Visual Studio仍会生成并执行代码。

1. The Visual Studio designer underlines the entire tag <MultiBinding ... </MultiBinding> in cyan.
2. The Error List window reports the error "Specified cast is not valid."
3. While it is displayed as an error, Visual Studio will still build and execute the code.

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