wpf - 使用 IDataError 进行验证

Question

我的 View 模型中有以下验证方法(示例仅显示一列“ItemNumber”):

public bool IsValid
{
  get
  {
    foreach (string property in ValidatedProperties)
      if (GetValidationError(property) != null)
        return false;

    return true;
  }
}

static readonly string[] ValidatedProperties = 
{ 
  "ItemNumber"
};

string GetValidationError(string propertyName)
{
  if (Array.IndexOf(ValidatedProperties, propertyName) < 0)
    return null;

  string error = null;

  switch (propertyName)
  {
    case "ItemNumber":
      error = this.ValidateItemNumber();
      break;
    default:
      Debug.Fail("Unexpected property being validated on ProjectExpense: " + propertyName);
      break;
  }
  // set the status message on the UI to the generated error
  if (error != null)
  {
    ErrorMessage = error;
  }

  return error;
}

// string method
static bool IsStringMissing(string value)
{
  return String.IsNullOrEmpty(value) || value.Trim() == String.Empty;
}

string ValidateItemNumber()
{
  if (SelectedProjectExpenseItem != null)
  {
    if (IsStringMissing(SelectedProjectExpenseItem.ItemNumber))
    {
      return "Item number is required";
    }
    if (SelectedProjectExpenseItem.ItemNumber.Length > 50)
    {
      return "Item number exceeds 50 characters";
    }
  }
  return null;
}

#endregion


#region IDataErrorInfo Members

string IDataErrorInfo.Error { get { return null; } }

string IDataErrorInfo.this[string propertyName]
{
  get { return this.GetValidationError(propertyName); }
}

验证触发，但我不知道如何将它传达给我的数据网格。我正在使用单独的 Dto(因此上面的 SelectedProjectExpenseItem.ItemNumber，SelectedProjectExpenseItem 是我的 Dto)，而不是直接在我的 View 模型中使用属性。这是我的数据网格:

  <DataGrid ItemsSource="{Binding Path=ListOfProjectExpenseItems}" AutoGenerateColumns="False" 
      Name="dgProjectExpenseItems" SelectionMode="Single" SelectionUnit="FullRow" CanUserResizeColumns="True" 
      SelectedItem="{Binding Path=SelectedProjectExpenseItem, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" GridLinesVisibility="Horizontal" CanUserDeleteRows="True" CanUserAddRows="True">
    <DataGrid.Columns>
      <DataGridTextColumn Header="ID" Width="SizeToCells" MinWidth="50" Binding="{Binding RowID}" />
      <DataGridTextColumn Header="Project Expense ID" Width="SizeToCells" Visibility="Hidden" MinWidth="0" Binding="{Binding ProjectExpenseID, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
      <DataGridTextColumn Header="Item Number" Width="SizeToCells" MinWidth="140" Binding="{Binding ItemNumber, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
      <DataGridTextColumn Header="Item Description" Width="SizeToCells" MinWidth="250" Binding="{Binding ItemDescription, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
      <DataGridTextColumn Header="Unit Price" Width="SizeToCells" MinWidth="90" Binding="{Binding ItemUnitPrice, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
      <DataGridTextColumn Header="Qty" Width="SizeToCells" MinWidth="65" Binding="{Binding ItemQty, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
      <DataGridTextColumn Header="Supplier Name" Width="SizeToCells" MinWidth="200" Binding="{Binding SupplierName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
    </DataGrid.Columns>
  </DataGrid>

我想使用一种样式，比如带有红色边框和说明错误的工具提示，来表示行或单元格有问题。然而，我发现的每个使用样式的示例都直接在 View 模型中具有属性，我无法弄清楚如何将其移植到我的 Dto 中。

任何帮助表示赞赏。

Answer 1

你有ValidatesOnDataErrors=True, ValidatesOnExceptions=True, NotifyOnValidationError=true活跃在你的绑定(bind)上？