Vb.net Don'；如果Datagridview中已经存在，则不添加值

我有一个“table_info”表，其中有一列ID、NAME 添加新ID时，请输入名称。我想检查一下它是否已经存在。如果存在，则生成一个MessageBox

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如何做到这一点

实现这一点的方法不止一种。如果没有太多行，可以检查datasource/set或实际的datagridview本身。如果是晚一点，你可以这样做：

如果满足以下条件，则Check函数返回true：

    Function IsInDatagridview(ByVal cell1 As String, ByVal cell2 As String, ByVal rowCell1_ID As Integer, ByVal rowCell2_ID As Integer, ByRef dgv As DataGridView)

    Dim isFound As Boolean = False

    For Each rw As DataGridViewRow In dgv.Rows
        If rw.Cells(rowCell1_ID ).Value.ToString = cell1 Then
            If rw.Cells(rowCell2_ID ).Value.ToString = cell2 Then

                isFound = True
                Return isFound


            End If
        End If
    Next

    Return isFound

End Function

    If (IsInDatagridview("id", "name", 0, 1, DataGridView1)) Then

        ''// Code to display message.
        MsgBox("Record Exists!", MsgBoxStyle.Information)

    End If

然后，如果满足条件，则使用该功能显示消息框：

    Function IsInDatagridview(ByVal cell1 As String, ByVal cell2 As String, ByVal rowCell1_ID As Integer, ByVal rowCell2_ID As Integer, ByRef dgv As DataGridView)

    Dim isFound As Boolean = False

    For Each rw As DataGridViewRow In dgv.Rows
        If rw.Cells(rowCell1_ID ).Value.ToString = cell1 Then
            If rw.Cells(rowCell2_ID ).Value.ToString = cell2 Then

                isFound = True
                Return isFound


            End If
        End If
    Next

    Return isFound

End Function

    If (IsInDatagridview("id", "name", 0, 1, DataGridView1)) Then

        ''// Code to display message.
        MsgBox("Record Exists!", MsgBoxStyle.Information)

    End If

您可能需要将ID更改为整数，但我认为它应该可以工作。我还没有测试过

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好的，那么这将要做的是迭代您指定的datagridview中的每一行“rw”，检查单元格列的字符串匹配情况，如果找到匹配项，则将“isFound”设置为true，然后返回“isFound”

Ypu必须将use

rowCell\u ID

作为字符串引用，因为它是datagridivew中的列名：

Function IsInDatagridview(ByVal cell1 As String, ByVal cell2 As String, ByVal rowCell1_ID As Integer, ByVal rowCell2_ID As Integer, ByRef dgv As DataGridView)

    Dim isFound As Boolean = False

    For Each rw As DataGridViewRow In dgv.Rows
        If rw.Cells("rowCell1_ID" ).Value.ToString = cell1 Then
            If rw.Cells("rowCell2_ID" ).Value.ToString = cell2 Then

                isFound = True
                Return isFound


            End If
        End If
    Next

    Return isFound

End Function

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是否要检查sqlserver表或datagridview。你累了什么。制作一个代码它不会工作，无论如何，非常感谢你的帮助。我明白了。