如何在sql参数列表中使用for循环？

Question

如何使用 dal 将我的数据 gridview 值添加到数据库中，我的代码是这样的

Dim list As New List(Of SqlParameter)

For each row as DataGridView In DataGridView1.Rows
    If row.cell(0).value isnot nothing
        Qry="insert into sale1(Description)values(@1)"
        With list
           .add(new Sqlparameter("@1",row.cells(2).value)
        End with
    End if
Next

Answer 1

如果您不想按照 cmets 中的 @jmcilhinney 建议的那样做（最好的方法），这应该与您提供的代码最接近，但它不会将数据库代码与用户界面代码分开。

这个想法是在循环外添加一次参数，然后在循环中更改值。我不得不猜测参数的数据类型和大小。请检查您的数据库并更正代码。

Private Sub OPCode2()
    Using cn As New SqlConnection("Your connection string"),
            cmd As New SqlCommand("insert into sale1 (Description)values(@1)", cn)
        cmd.Parameters.Add("@1", SqlDbType.NVarChar, 300)
        cn.Open()
        For Each row As DataGridViewRow In DataGridView1.Rows
            If row.Cells(0).Value IsNot Nothing Then
                cmd.Parameters("@1").Value = row.Cells(2).Value
                cmd.ExecuteNonQuery()
            End If
        Next
    End Using
End Sub

要分离代码...

Private Sub UICode()
    Dim lst As New List(Of String)
    For Each row As DataGridViewRow In DataGridView1.Rows
        If row.Cells(0).Value IsNot Nothing Then
            lst.Add(row.Cells(2).Value.ToString)
        End If
    Next
    UpdateDatabase(lst)
End Sub

Private Sub UpdateDatabase(lst As List(Of String))
    Using cn As New SqlConnection("Your connection string"),
            cmd As New SqlCommand("insert into sale1 (Description)values(@1)", cn)
        cmd.Parameters.Add("@1", SqlDbType.NVarChar, 300)
        cn.Open()
        For Each s As String In lst
            cmd.Parameters("@1").Value = s
            cmd.ExecuteNonQuery()
        Next
    End Using
End Sub