VB.NET中同一窗体兼具查看/编辑时如何禁用DataGridView RowValidating事件

在FormTransaction中添加模式标识字段区分操作模式，在RowValidating事件中根据标识决定是否执行校验逻辑即可解决问题：

修改后的FormTransaction代码 #

Public Class FormTransaction
    Private list As New List(Of Product)() From {
        New Product With {
        .Codeproduct = "1000",
        .Qty = 20,
        .Qty_Stock = 0
        },
        New Product With {
        .Codeproduct = "2000",
        .Qty = 30,
        .Qty_Stock = 40
        }
    }
    Private listnew As New List(Of Product)()
    ' 新增模式标识字段，默认处于添加模式
    Private IsViewEditMode As Boolean = False

    Public Sub New()
        InitializeComponent()

        Dim bindingList As New BindingList(Of Product)(CType(listnew, IList(Of Product)))
        Dim source = New BindingSource(bindingList, Nothing)
        DataGridView1.DataSource = source
    End Sub

    Public Sub New(Invno As Product)
        Me.New()
        ' 切换为查看/编辑模式
        IsViewEditMode = True
        DataGridView1.DataSource = list
    End Sub

    Private Sub DataGridView1_RowValidating(sender As Object, e As DataGridViewCellCancelEventArgs) Handles DataGridView1.RowValidating
        ' 查看/编辑模式下直接跳过校验逻辑
        If IsViewEditMode Then Return

        Dim transferredQTY As Integer
        Dim onHandQTY As Integer

        With DataGridView1.Rows(e.RowIndex)
            Try
                transferredQTY = Convert.ToInt32(.Cells("Qty").Value)
            Catch ex As Exception
                transferredQTY = 0
            End Try
            Try
                onHandQTY = Convert.ToInt32(.Cells("Qty_Stock").Value)
            Catch ex As Exception
                onHandQTY = 0
            End Try
            If transferredQTY > onHandQTY Then
                MessageBox.Show("Please check don't Have sufficient quantity Stock" & "Only have Stock " & onHandQTY & " Pcs", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
                e.Cancel = True
            End If
        End With
    End Sub
End Class

修改说明 #

1. 新增IsViewEditMode私有字段，默认值为False，对应添加模式
2. 在带参数的构造函数（查看/编辑模式入口）中，将IsViewEditMode设为True
3. 在RowValidating事件开头增加判断：如果处于查看/编辑模式，直接退出事件，不执行库存校验逻辑

修改后，点击BtnViewEdit打开窗体时不会触发库存不足的错误提示；点击BtnAdd时，库存校验逻辑正常生效。

内容的提问来源于stack exchange，提问作者user22579796