问题

I tried to referesh via the button then I deleted the grid then an error appeared even though I had made grid.ondelete false. Is there any solution so I can avoid the error

' 译文：我尝试通过按钮刷新，然后删除了表格，然后出现了错误，尽管我已将grid.ondelete设置为false。是否有解决方案以避免这个错误

Thanks
' 译文：谢谢

Public Class Form1
    Private uService As New UserService()
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Grid.ReadOnly = True
        Grid.OnDelete(Of User)(Function(r, row)
                                   Return False
                               End Function)
        LoadData()
    End Sub
    Private Sub LoadData()
        Dim user = uService.GetUser()
        Grid.Bind(user)
    End Sub
    Private Sub btnrefresh_Click(sender As Object, e As EventArgs) Handles btnrefresh.Click
        LoadData()
    End Sub
End Class

Public Module DbContext
    Public Function GetOledbConnectionString() As String
        Return "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\dapperdemo.accdb;Persist Security Info=False;"
    End Function
End Module

Public Class UserService
    Private ReadOnly _conn As OleDbConnection
    Private _connectionString As String = DbContext.GetOledbConnectionString()
    Public Sub New()
        _conn = New OleDbConnection(_connectionString)
    End Sub
    Public Function GetUser() As IEnumerable(Of User)
        Dim sql = "SELECT * FROM Users"
        Using _conn = New OleDbConnection(DbContext.GetOledbConnectionString())
            Return _conn.Query(Of User)(sql).ToList()
        End Using
    End Function
End Class
End Class

' 译文：来自诊断工具的结果，这是从Visual Studio复制粘贴的
Culture=neutral, PublicKeyToken=b77a5c561934e089</ExceptionType><Message>Value cannot be null.
Parameter name: key</Message><StackTrace>   at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at    at Kimtoo.BindingProvider.DGVBindingProvider.&amp;amp;lt;&amp;amp;gt;c__DisplayClass29_0`1.&amp;amp;lt;Bind&amp;amp;gt;b__3(Object s, DataGridViewRowCancelEventArgs e)

<details>
<summary>英文:</summary>

I tried to referesh via the button then I deleted the grid then an error appeared even though I had made grid.ondelete false. Is there any solution so I can avoid the error


Thanks

Public Class Form1
Private uService As New UserService()
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Grid.ReadOnly = True
Grid.OnDelete(Of User)(Function(r, row)
Return False
End Function)
LoadData()
End Sub
Private Sub LoadData()
Dim user = uService.GetUser()
Grid.Bind(user)
End Sub
Private Sub btnrefresh_Click(sender As Object, e As EventArgs) Handles btnrefresh.Click
LoadData()
End Sub
End Class
Public Module DbContext
Public Function GetOledbConnectionString() As String
Return "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\dapperdemo.accdb;Persist Security Info=False;"
End Function
End Module
Public Class UserService
Private ReadOnly _conn As OleDbConnection
Private _connectionString As String = DbContext.GetOledbConnectionString()
Public Sub New()
_conn = New OleDbConnection(_connectionString)
End Sub
Public Function GetUser() As IEnumerable(Of User)
Dim sql = "SELECT * FROM Users"
Using _conn = New OleDbConnection(DbContext.GetOledbConnectionString())
Return _conn.Query(Of User)(sql).ToList()
End Using
End Function
End Class
End Class

[![Value cannot be null][1]][1]

'result from diagnostic tools This is a copy paste from visual studio
Culture=neutral, PublicKeyToken=b77a5c561934e089</ExceptionType><Message>Value cannot be null.
Parameter name: key</Message><StackTrace> at System.Collections.Generic.Dictionary2.FindEntry(TKey key)
at System.Collections.Generic.Dictionary2.get_Item(TKey key)
at at Kimtoo.BindingProvider.DGVBindingProvider.&amp;lt;&amp;gt;c__DisplayClass29_0`1.&amp;lt;Bind&amp;gt;b__3(Object s, DataGridViewRowCancelEventArgs e)

  [1]: https://i.stack.imgur.com/jJ57u.jpg

</details>


# 答案1
**得分**: 1

我的解决方案是阻止或关闭绑定提供程序的ondelete事件，即在datagridview keypress中与键盘删除按钮相关的事件。

```vb
Private Sub Grid_KeyDown(sender As Object, e As KeyEventArgs) Handles Grid.KeyDown
    Try
        If e.KeyCode = Keys.Delete AndAlso e.KeyValue = 46 Then &#39; 删除键
            e.Handled = True
        End If
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try
End Sub

    Private Sub Grid_KeyDown(sender As Object, e As KeyEventArgs) Handles Grid.KeyDown
        Try
    If e.KeyCode = Keys.Delete AndAlso e.KeyValue = 46 Then ' Delete Key
    e.Handled = True
    End If
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub