visual-studio-2010 - Visual basic从最后一个数据网格表单传递值并将其更新为新表单

Question

我的代码有问题。问题是我无法获取 ID。

这是我的代码。

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

        txtID.Text = PassName
        txtName.Text = PassID
        cqty.Text = Passqty
        cucost.Text = Passucost
        ctotal.Text = Passtotal
    End Sub
    Private Sub Updatebtn()
        tqty.Text = Val(cqty.Text) + Val(qtyText.Text)
        tucost.Text = Val(cucost.Text) + Val(cucost.Text)
        ttotal.Text = Val(tucost.Text) * Val(tqty.Text)
        Dim sql As String = "UPDATE tblPurchase SET itemQuantity='" + tqty.Text + "',UnitCost='" + tucost.Text + "',TotalCost='" + ttotal.Text + "'WHERE purchaseID='" + txtName.Text + "'"
        Try
            con.Open()
            If cmd.ExecuteNonQuery() > 0 Then
                MsgBox("Purchased Successfully Updated")
                cleartxt()
            End If
            con.Close()

        Catch ex As Exception
            MsgBox(ex.Message)
            con.Close()
        End Try
    End Sub