Datagridview - 防止组合框单元格中的重复

Question

我在 Datagridview 的第一个单元格中有一个 ComboboxCell。这个组合框有来自我的数据库的数据源。当我从中选择项目时，一行中的所有其他单元格都将由我的数据库中的记录填充。现在我想根据 Comboboxcell 选定的项目来防止重复的行条目。之后，我想清除该 Comboboxcell，并保持代码运行。我设法做了几乎所有事情，但问题是在显示 msgbox 后，代码停止工作 - 所以当我再次选择 ComboboxCell Item 时，即使在新行中也没有任何反应。这是我的全部代码：

 Private Sub My_DGV_CellValueChanged(sender As Object, e As DataGridViewCellEventArgs) Handles My_DGV.CellValueChanged

        If My_DGV.Columns(e.ColumnIndex).Name = "Column1" Then

            'Prevent duplicates
            For i As Integer = 0 To My_DGV.RowCount - 2
                For j As Integer = i + 1 To My_DGV.RowCount - 2
                    If My_DGV.Rows(i).Cells(0).Value = My_DGV.Rows(j).Cells(0).Value Then
                        MsgBox("You allready selected this item. Duplicates are not allowed.", MsgBoxStyle.Information, "Warning")
                        My_DGV.Rows(j).Cells(0).Value = " "
                        Dim cbx As ComboBox = DGV_APO.EditingControl
                        cbx.SelectedIndex = -1
                        Exit Sub
                     End If

                 Next
             Next

            OracleconnOpen()

            Using cmd As New OracleCommand()

                Dim SQL As String = "Select NAMES,SURNAMES,STATE FROM My_Table"
                Dim Concat_SQL As String = " Where "
                SQL = String.Concat(SQL, Concat_SQL, " ID_NUMBER = :id")
                cmd.Parameters.Add(New OracleParameter("id", My_DGV.CurrentRow.Cells(0).Value))
                cmd.Connection = OracleconnOpen()
                cmd.CommandText = SQL
                cmd.CommandType = CommandType.Text

                Dim dr As OracleDataReader = cmd.ExecuteReader()
                Dim dt As New DataTable
                dt.Load(dr)

                My_DGV.CurrentRow.Cells(1).Value = dt.Rows(0)("NAMES").ToString()
                My_DGV.CurrentRow.Cells(2).Value = dt.Rows(0)("SURNAMES").ToString()
                My_DGV.CurrentRow.Cells(3).Value = dt.Rows(0)("STATE").ToString()

            End Using

            OracleconnClose()

        End If

 End Sub

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        'SELECT from my DB
        Dim SQL As String = "SELECT ID_NUMBER from My_Table"
        Dim dtb As New DataTable()

        Try

            OracleconnOpen() 'Open my connection

            Using dad As New OracleDataAdapter(SQL, OracleconnOpen)
                dad.Fill(dtb)
            End Using

            Column1.DisplayMember = "ID_NUMBER"
            Column1.DataSource = dtb

        Catch ex As Exception
            MessageBox.Show(ex.Message)

        Finally

            OracleconnClose() 'Close my connection
        End Try

 End Sub

 Private Sub My_DGV_CurrentCellDirtyStateChanged(sender As Object, e As EventArgs) Handles My_DGV.CurrentCellDirtyStateChanged

        If My_DGV.IsCurrentCellDirty Then My_DGV.CommitEdit(DataGridViewDataErrorContexts.Commit)

 End Sub

 Private Sub My_DGV_DataError(sender As Object, e As DataGridViewDataErrorEventArgs) Handles DGV_APO.DataError

        e.ThrowException = False
 End Sub

那么，我做错了什么？任何帮助表示赞赏。

Answer 1

您的循环中有一个 Exit Sub 调用，该调用将始终执行，因此当您更改此值时，exit sub 之后的任何内容都不会运行。如果您想在找到重复项后退出循环并继续运行代码，则应在 If 语句中完成。即使第一行不匹配，此代码也应在比较第一行后停止工作。