没有为类型dbnull定义运算符'*' [英] Operator '*' is not defined for type dbnull

问题描述

Hii，我想要乘以datagridview cells值。但当我执行程序时，它显示"运算符'*'未定义为类型Dbnull，而类型DbNull"

Hii, i am tring to multiply datagridview cells value. but when i execute prograam it show " Operator '*' is not defined for type Dbnull and for type DbNull"

这里是我的代码

 Private Sub DataGridView1_CellValueChanged(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellValueChanged
       
        For row As Integer = 0 To DataGridView1.Rows.Count - 1
            If IsDBNull(DataGridView1.Rows(row).Cells(7).Value) Then
                Console.WriteLine("Null detected")
            Else
                Console.WriteLine(DataGridView1.Rows(row).Cells(7).Value)
                Me.DataGridView1(7, e.RowIndex).Value = Me.DataGridView1(5, e.RowIndex).Value * Me.DataGridView1(6, e.RowIndex).Value
                'Me.DataGridView1(7, e.RowIndex).Value = purchase

            End If
        Next

        
    End Sub

任何人都可以帮助解决这个问题。

can anyone help to solve this problem.

谢谢&问候

推荐答案

试试

        For row As Integer = 0 To DataGridView1.Rows.Count - 1
            If DataGridView1.Rows(row).Cells(7).Value IsDbNull.Value Then
                Console.WriteLine("Null detected")
            Else
                Console.WriteLine(DataGridView1.Rows(row).Cells(7).Value)
                Me.DataGridView1(7, e.RowIndex).Value = Me.DataGridView1(5, e.RowIndex).Value * Me.DataGridView1(6, e.RowIndex).Value
                'Me.DataGridView1(7, e.RowIndex).Value = purchase

            End If
        Next

        
    End Sub

您也可以选择严格选项。您应该将您的值转换或转换为数字类型（IE：int32，double等）

also you may wish to turn option strict on. You should be casting or converting your values as numeric type (IE: int32, double, etc)

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