mysql - Vb和MySQL连接和代码错误

Question

大家好，我又卡住了，当表单加载时，我收到错误:“连接错误:位置 0 处没有行”求助!？

 Private Sub frmadduser_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim sqlDT As New DataTable
    txtlname.Text = ""
    txtfname.Text = ""
    txtaddress.Text = ""
    txtcontact.Text = ""
    Try
        If Me.Text = "Edit Account" Then
            sqlSTR = "SELECT * FROM users WHERE idUsers =" & FrmSYSUSER.lstusers.FocusedItem.Text
            ExecuteSQLQuery(sqlSTR)
            MsgBox(sqlDT.Rows(0)("Username"))
            With sqlDT
                If .Rows.Count > 0 Then
                    txtlname.Text = .Rows(0)("lname")
                    txtfname.Text = .Rows(0)("fname")
                    txtaddress.Text = .Rows(0)("address")
                    txtcontact.Text = .Rows(0)("contact")
                    txtusername.Text = .Rows(0)("username")
                    txtpassword.Text = .Rows(0)("password")
                    txtconfirm.Text = .Rows(0)("password")
                    cmbaccnttype.Text = .Rows(0)("accesstype")
                End If
            End With
        End If
    Catch ex As Exception
        MsgBox("Connection Error :" & ex.Message, MsgBoxStyle.Information, xTitlename)
    End Try
End Sub

Answer 1

如果您ExecuteSQLQuery(sqlSTR)返回一个DataTable，您可能会这样做:

  sqlDT = ExecuteSQLQuery(sqlSTR)

并在对其执行任何操作之前检查是否有行，例如:

 if (sqlDT.Rows.Count>0) Then
    With sqlDT
         txtlname.Text = .Rows(0)("lname")
         txtfname.Text = .Rows(0)("fname")
         txtaddress.Text = .Rows(0)("address")
         txtcontact.Text = .Rows(0)("contact")
         txtusername.Text = .Rows(0)("username")
         txtpassword.Text = .Rows(0)("password")
         txtconfirm.Text = .Rows(0)("password")
         cmbaccnttype.Text = .Rows(0)("accesstype")
    End With
 End If