DataGridTextColumn.MaxLength?
-
20-09-2019 - |
题
我如何设置DataGridTextColumn的MaxLength属性?
解决方案
<tk:DataGridTextColumn Binding="{Binding Text}">
<tk:DataGridTextColumn.EditingElementStyle>
<Style TargetType="TextBox">
<Setter Property="MaxLength" Value="16"/>
</Style>
</tk:DataGridTextColumn.EditingElementStyle>
</tk:DataGridTextColumn>
你也可以设置它使用以下行为,所以你不必使用样式和setter每次:
Public Class TextBoxBehavior
Private Shared Types As Type() = New Type() {GetType(AutoCompleteBox), GetType(ComboBox), GetType(DataGridTextColumn)}
Public Shared Function GetMaxLength(ByVal element As DependencyObject) As Integer
Return element.GetValue(MaxLengthProperty)
End Function
Public Shared Sub SetMaxLength(ByVal element As DependencyObject, ByVal value As Integer)
element.SetValue(MaxLengthProperty, value)
End Sub
Private Shared Sub ValidateElement(ByVal element As DependencyObject)
If element Is Nothing Then Throw New ArgumentNullException("element")
If Not Types.Contains(element.GetType) Then Throw New NotSupportedException("The TextBoxBehavior is not supported for the given element")
End Sub
Public Shared ReadOnly MaxLengthProperty As DependencyProperty =
DependencyProperty.RegisterAttached("MaxLength",
GetType(Integer), GetType(TextBoxBehavior),
New FrameworkPropertyMetadata(Integer.MaxValue, AddressOf TextBox_MaxLengthChanged))
Private Shared Sub TextBox_MaxLengthChanged(ByVal sender As Object, ByVal e As DependencyPropertyChangedEventArgs)
If sender Is Nothing Then Exit Sub
Dim value = DirectCast(e.NewValue, Integer)
If TypeOf sender Is AutoCompleteBox Then
Dim acb = DirectCast(sender, AutoCompleteBox)
If acb.IsLoaded Then
Dim tb = DirectCast(acb.Template.FindName("Text", acb), TextBox)
tb.MaxLength = value
Else
acb.AddHandler(AutoCompleteBox.LoadedEvent, New RoutedEventHandler(AddressOf Element_Loaded))
End If
ElseIf TypeOf sender Is ComboBox Then
Dim cb = DirectCast(sender, ComboBox)
If cb.IsLoaded Then
Dim tb = DirectCast(cb.Template.FindName("PART_EditableTextBox", cb), TextBox)
tb.MaxLength = value
Else
cb.AddHandler(ComboBox.LoadedEvent, New RoutedEventHandler(AddressOf Element_Loaded))
End If
ElseIf TypeOf sender Is DataGridTextColumn Then
Dim dgtc = DirectCast(sender, DataGridTextColumn)
Dim setter = GetIsMaxLengthSet(dgtc.EditingElementStyle)
If setter Is Nothing Then
Dim style = New Style(GetType(TextBox), dgtc.EditingElementStyle)
style.Setters.Add(New Setter(TextBox.MaxLengthProperty, value))
dgtc.EditingElementStyle = style
style.Seal()
Else
setter.Value = value
End If
End If
End Sub
Private Shared Function GetIsMaxLengthSet(ByVal style As Style) As Setter
If style Is Nothing Then Return Nothing
Dim setter = style.Setters.LastOrDefault(Function(s) TypeOf s Is Setter AndAlso DirectCast(s, Setter).Property Is TextBox.MaxLengthProperty)
If setter IsNot Nothing Then Return setter Else Return GetIsMaxLengthSet(style.BasedOn)
End Function
Private Shared Sub Element_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
Dim ml = GetMaxLength(sender)
TextBox_MaxLengthChanged(sender, New DependencyPropertyChangedEventArgs(TextBox.MaxLengthProperty, -1, ml))
sender.RemoveHandler(FrameworkElement.LoadedEvent, New RoutedEventHandler(AddressOf Element_Loaded))
End Sub
End Class
用法:
<ComboBox xmlns:loc="MyNamesapace" loc:TextBoxBehavior.MaxLength="50" />
其他提示
如果你把所有的列之间共享的风格,你想一个额外的样式添加到一个或更多的这些,你可以使用Style.BasedOn属性:
<DataGridTextColumn Binding="{Binding SomeProperty, UpdateSourceTrigger=PropertyChanged}" ElementStyle="{StaticResource CellErrorStyle}">
<DataGridTextColumn.EditingElementStyle>
<Style TargetType="TextBox" BasedOn="{StaticResource OriginalStyleKey}">
<Setter Property="MaxLength" Value="5" />
</Style>
</DataGridTextColumn.EditingElementStyle>
</DataGridTextColumn>
<Window.Resources>
<Style x:Key="sty_txtDesc" TargetType="TextBox">
<Setter Property="MaxLength" Value="495" />
</Style>
</Window.Resources>
for (int i = 0; i < miDataGridX.Columns.Count; i++)
{
if (miDataGridX.Columns[i].Header.ToString() == "Description")
{
((DataGridTextColumn)miDataGridX.Columns[i]).EditingElementStyle = (Style)this.FindResource("sty_txtDesc");
}
}
不隶属于 StackOverflow