Question

     For i As Integer = Me.DataGridView1.SelectedRows.Count - 1 To 0 Step -1
            Dim due_date As Object
            Dim calc As TimeSpan
            due_date = DataGridView1.Rows(i).Cells(3).Value()
**error** ---->>>calc = Today.Subtract(due_date)<<<--------**error**
            MessageBox.Show(calc.ToString)
            Dim Query As String
            Query = "delete from periodicals where student_id= '" & Me.DataGridView1.SelectedRows(i).Cells(0).Value.ToString() & "'"
            COMMAND = New MySqlCommand(Query, MysqlConn)
            SDA.SelectCommand = COMMAND
            SDA.Fill(dbDataSet)
            bSource.DataSource = dbDataSet
            Me.DataGridView1.Rows.Remove(Me.DataGridView1.SelectedRows(i))
            DataGridView1.DataSource = bSource
            SDA.Update(dbDataSet)

我试图在datagridview中减去今天和截止日期，并将通过消息框显示。我对如何解决这个问题一无所知。建议

Answer 1

＆＃34;模糊匹配＆＃34;错误可能是因为due_date被实例化为Object。减法函数不知道要从哪个数据类型中减去。

也许试试：

Dim due_date As DateTime

希望对你有用！

Answer 2

     Dim due As Date
    Dim calc As TimeSpan
    Dim d1 As Date

    Try
        MysqlConn.Open()
        For i As Integer = Me.DataGridView1.SelectedRows.Count - 1 To 0 Step -1
            d1 = Format(Now, "yyyy-MM-dd")
            due = DataGridView1.Rows(i).Cells(3).Value()
            calc = d1.Subtract(due)
            Dim fine As Integer = calc.Days * 20
            If MessageBox.Show("Your Penalty is:₱" & fine & "" + vbNewLine + " Do you want to remove this as paid ?", "Informed", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = Windows.Forms.DialogResult.Yes Then
                Dim Query As String
                Query = "delete from periodicals where student_id= '" & Me.DataGridView1.SelectedRows(i).Cells(0).Value.ToString() & "'"
                COMMAND = New MySqlCommand(Query, MysqlConn)
                SDA.SelectCommand = COMMAND
                SDA.Fill(dbDataSet)

感谢您的建议，最终它按照我希望的方式运作。

Ambigious Match异常未得到处理

2 个答案: