wpf - 带有静态文本和绑定(bind)的标签

Question

我正在尝试获取一个标签以显示特定文本，同时还绑定(bind)到 VB.Net 代码中的变量。我可以进行绑定(bind)，但无法添加静态文本。

到目前为止我所拥有的:

<Label x:Name="TestLabel" Content="{Binding Path=Row, StringFormat='Row #{0}'}" 
                          HorizontalAlignment="Left" 
                          Height="35" 
                          Margin="203,21,0,0" 
                          VerticalAlignment="Top" 
                          Width="83" 
                          FontSize="18">

和

Public Class Row
    Implements INotifyPropertyChanged

    Private _Row As Byte
    Public Property Row() As Byte
        Get
            Return _Row
        End Get
        Set(ByVal value As Byte)
            _Row = value

            OnPropertyChanged(New PropertyChangedEventArgs("Row"))
        End Set
    End Property

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

    Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
        If Not PropertyChangedEvent Is Nothing Then
            RaiseEvent PropertyChanged(Me, e)
        End If
    End Sub
End Class

和

Private Rows As New Row

Public Sub New()
    InitializeComponent()
    TestLabel.DataContext = Rows
    Rows.Row = MyTextBox.Text.HandledStringtoSByte
End Sub

扩展代码(因为我有一个自定义扩展):

''' <summary>
''' Handles conversion of string variable to Tiny Integer
''' </summary>
''' <param name="s"></param>
''' <param name="I">Returned if conversion fails.</param>
''' <returns>Signed 8bit Integer</returns>
''' <remarks></remarks>
<Runtime.CompilerServices.Extension()> _
Public Function HandledStringtoSByte(ByRef S As String, Optional I As SByte = 0) As SByte
    Try
        If S = String.Empty Then
            Return I
        Else
            Return SByte.Parse(S)
        End If
    Catch
        Dim result As String = String.Empty
        Dim ReturnByte As SByte
        Dim Parsed As Byte
        For Each Character In S.ToCharArray
            If Character = "-" Then
                If S.Substring(0, 1).ToString <> "-" Then
                    Exit For
                End If
            End If
            If Character = "." Then
                Exit For
            End If
            If Byte.TryParse(Character, Parsed) Then
                result = result + Parsed.ToString
            End If
        Next
        If result <> String.Empty Then
            If SByte.TryParse(result, ReturnByte) Then
                Return SByte.Parse(ReturnByte)
            Else
                If Short.Parse(result) > Short.Parse(SByte.MaxValue.ToString) Then
                    Return SByte.MaxValue
                ElseIf Short.Parse(result) < Short.Parse(SByte.MinValue.ToString) Then
                    Return SByte.MinValue
                Else
                    Return SByte.Parse(ReturnByte)
                End If
            End If
        Else
            Return I
        End If
    End Try
End Function

现在我认为在绑定(bind)中使用 stringformat 会添加静态文本并将绑定(bind)变量放入 {0} 点，但给我的只是标签中的绑定(bind)变量。

我究竟做错了什么？

Answer 1

绑定(bind)目标是Content属性是 Object类型，这就是为什么你不能使用 StringFormat具有约束力。

而是使用 ContentStringFormat属性(property)

<Label Content="{Binding Path=Row}"  
       ContentStringFormat="Row #{0}" />

另一种方法:在 ViewModel 中创建只读属性，它将以所需格式表示值

Private _Row As Byte
Public Property Row() As Byte
    Get
        Return _Row
    End Get
    Set(ByVal value As Byte)
        _Row = value
        OnPropertyChanged(New PropertyChangedEventArgs("Row"))
        OnPropertyChanged(New PropertyChangedEventArgs("RowText"))
    End Set
End Property

Public ReadOnly Property RowText As String
    Get
        Return String.Format("Row #{0}", Me.Row)
    End Get
End Property

然后将此属性绑定(bind)到 View

<Label Content="{Binding Path=RowText}"/>