WPF DataGrid 验证错误未清除 [英] WPF DataGrid validation errors not clearing

问题描述

所以我有一个 WPF DataGrid，它绑定到一个 ObservableCollection.该集合通过 IDataErrorInfo 对其成员进行了验证.如果我以某种方式编辑单元格以使其无效，然后在按 Enter 键之前将其移开，然后返回并使其有效，则该单元格将停止显示无效，但是，！"行首仍然存在，并且 ToolTip 将引用之前的无效值.

解决方案

Not using Mode=TwoWay for DataGridTextColumns 解决了一个版本的问题，但是似乎这问题也可能由于其他原因而突然出现.

(任何对为什么不使用 Mode=TwoWay 有很好解释的人首先解决这个问题可能接近解决这个问题)

同样的事情发生在我的 DataGridComboBoxColumn 上，所以我试图更深入地挖掘.

问题不在于 Control 中的 Binding 显示 DataGridHeaderBorder 内的 ErrorTemplate.它正在将其 Visibility 绑定到祖先 DataGridRow 的 Validation.HasError(正如它应该做的那样)并且该部分正在工作.>

Visibility="{Binding (Validation.HasError),转换器={StaticResource bool2VisibilityConverter},RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}}}"/>

问题是验证错误一旦解决就不会从 DataGridRow 中清除.在我的问题版本中，DataGridRow 以 0 个错误开始.当我输入一个无效值时，它得到了 1 个错误，到目前为止一切顺利.但是当我解决错误时，它跳到了 3 个错误，所有这些错误都是一样的.

在这里我尝试使用 DataTrigger 解决它，如果 Validation.Errors 将 ValidationErrorTemplate 设置为 {x:Null}.Count 不是 1.它在第一次迭代中效果很好，但是一旦我第二次清除了错误，它又回来了.它不再有 3 个错误，它有 7 个！经过几次迭代后，它超过了 10.

我还尝试通过在 BindingExpressions 上执行 UpdateSource 和 UpdateTarget 手动清除错误，但没有骰子.Validation.ClearInvalid 也没有任何影响.在 Toolkit 中查看源代码并没有让我找到任何地方:)

所以我对此没有任何好的解决方案，但我认为无论如何我都应该发布我的发现..

到目前为止，我唯一的解决方法"是在 DataGridRowHeader

中隐藏 ErrorTemplate

<DataGrid.RowStyle><Style TargetType="DataGridRow"><Setter Property="ValidationErrorTemplate" Value="{x:Null}"/></风格></DataGrid.RowStyle><!-- ... --></DataGrid>

So I have a WPF DataGrid, which is bound to an ObservableCollection. The collection has validation on its members, through IDataErrorInfo. If I edit a cell in a way so as to be invalid, and then tab away from it before hitting enter, then come back and make it valid, the cell will stop showing invalid, however, the "!" at the head of the row will still be there, and the ToolTip will reference the previous, invalid value.

解决方案

Not using Mode=TwoWay for DataGridTextColumns solves one version of the problem, however it seems that this problem can appear out of nowhere for other reasons as well.

(Anyone who has a good explanation as of why not using Mode=TwoWay solves this in the first place is probably close to a solution to this problem)

The same thing just happened to me with a DataGridComboBoxColumn so I tried to dig a little deeper.

The problem isn't the Binding in the Control that displays the ErrorTemplate inside DataGridHeaderBorder. It is binding its Visibility to Validation.HasError for the ancestor DataGridRow (exactly as it should be doing) and that part is working.

Visibility="{Binding (Validation.HasError),
                     Converter={StaticResource bool2VisibilityConverter},
                     RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}}}"/>

The problem is that the validation error isn't cleared from the DataGridRow once it is resolved. In my version of the problem, the DataGridRow started out with 0 errors. When I entered an invalid value it got 1 error so, so far so good. But when I resolved the error it jumped up to 3 errors, all of which were the same.

Here I tried to resolve it with a DataTrigger that set the ValidationErrorTemplate to {x:Null} if Validation.Errors.Count wasn't 1. It worked great for the first iteration but once I cleared the error for the second time it was back. It didn't have 3 errors anymore, it had 7! After a couple of more iterations it was above 10.

I also tried to clear the errors manually by doing UpdateSource and UpdateTarget on the BindingExpressions but no dice. Validation.ClearInvalid didn't have any effect either. And looking through the source code in the Toolkit didn't get me anywhere :)

So I don't have any good solutions to this but I thought I should post my findings anyway..

My only "workaround" so far is to just hide the ErrorTemplate in the DataGridRowHeader

<DataGrid ...>
    <DataGrid.RowStyle>
        <Style TargetType="DataGridRow">
            <Setter Property="ValidationErrorTemplate" Value="{x:Null}"/>
        </Style>
    </DataGrid.RowStyle>
    <!-- ... -->
</DataGrid>

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