此模块vb.net的调试信息中缺少源信息

Question

您好我正在尝试执行一个简单的代码，它为上面提到了附加信息＆＃34; Column＆＃39; Service_Type_ID＆＃39;被限制为独特的。价值＆＃39; S2＆＃39;已经存在＆＃34;。 我是编程新手。请帮帮我。

当我尝试从组合框中选择项目并将其索引传递给文本框时，我得到此异常。代码的stared部分是为了那个

Dim cmd As SqlCommand = New SqlCommand
Dim con As New SqlConnection("Data Source=CHAMIKA\SQLEXPRESS; Initial Catalog=MyHotelManagementSystem; Integrated Security=True")

Private Function ValidData() As Boolean
    If String.IsNullOrEmpty(Me.txtBoxID.Text) Then
        MessageBox.Show("Service ID is empty.")
        Me.txtBoxID.Focus()
        Return False
    End If

    If String.IsNullOrEmpty(Me.cmbSerType.Text) Then
        MessageBox.Show("Service Type is empty.")
        Me.cmbSerType.Focus()
        Return False
    End If

    If String.IsNullOrEmpty(Me.txtBoxName.Text) Then
        MessageBox.Show("Service Name is empty.")
        Me.txtBoxName.Focus()
        Return False
    End If

    If String.IsNullOrEmpty(Me.txtBoxRate.Text) Then
        MessageBox.Show("Service Rate is empty.")
        Me.txtBoxRate.Focus()
        Return False
    End If

    Return True
End Function

**Private Sub cmbSerType_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbSerType.SelectedIndexChanged
    Try
        Dim selectedVal = cmbSerType.SelectedValue
        txtBoxTypeID.Text = selectedVal
    Catch ex As Exception
    End Try
End Sub**

Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
    Dim cmd As SqlCommand = New SqlCommand
    If ValidData() Then
        Try
            cmd.Connection = con
            con.Open()
            cmd.CommandType = System.Data.CommandType.Text
            cmd.CommandText = "Insert Into dbo.Service (Service_ID,Service_Type_ID,Name,Rate) Values (@ServID,@TypeID,@Name,@Rate) "
            cmd.Parameters.AddWithValue("@ServID", txtBoxID.Text)
            cmd.Parameters.AddWithValue("@TypeID", txtBoxTypeID.Text)
            cmd.Parameters.AddWithValue("@Name", txtBoxName.Text)
            cmd.Parameters.AddWithValue("@Rate", txtBoxRate.Text)
            cmd.ExecuteNonQuery()
            MsgBox("Succesfully Added", MsgBoxStyle.Information, "add")
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
        If Not ValidData() Then
            Exit Sub
        End If
        con.Close()
        txtBoxID.Clear()
        txtBoxName.Clear()
        txtBoxRate.Clear()
        'txtBoxSerID.Clear()
    End If
End Sub

Private Sub Service_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    'TODO: This line of code loads data into the 'MyHotelManagementSystemDataSet26.Service_Type' table. You can move, or remove it, as needed.
    Me.Service_TypeTableAdapter.Fill(Me.MyHotelManagementSystemDataSet26.Service_Type)
    'TODO: This line of code loads data into the 'MyHotelManagementSystemDataSet25.Service' table. You can move, or remove it, as needed.
End Sub


Private Sub btnSerach_Click(sender As Object, e As EventArgs) Handles btnSerach.Click
    Dim cmd As SqlCommand = New SqlCommand
    DataGridView2.Columns.Clear()
    Dim stm As String
    con.Open()
    stm = "SELECT * FROM Service"


    cmd.CommandType = CommandType.Text
    cmd.CommandText = stm
    cmd.Connection = con

    da = New SqlDataAdapter(cmd)

    dt = New DataTable
    da.Fill(dt)

    Dim cb As New SqlCommandBuilder(da)
    With DataGridView2
        .AutoGenerateColumns = True
        .DataSource = dt
    End With

    cmd.Dispose()
    cmd = Nothing
    con.Close()
End Sub



Private Sub DataGridView_CellClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView2.CellClick
    Dim i As Integer
    i = DataGridView2.CurrentRow.Index
    If i >= 0 Then
        Me.txtBoxID.Text = DataGridView2.Item(0, i).Value
        Me.txtBoxTypeID.Text = DataGridView2.Item(1, i).Value
        Me.txtBoxName.Text = DataGridView2.Item(2, i).Value
        Me.txtBoxRate.Text = DataGridView2.Item(3, i).Value
    Else
        MessageBox.Show("Empty Row Clicked")
    End If
End Sub


Private Sub butnUpdate_Click(sender As Object, e As EventArgs) Handles butnUpdate.Click
    Dim cmd As SqlCommand = New SqlCommand
    Try
        cmd.Connection = con
        con.Open()

        cmd.CommandText = "UPDATE Service SET Service_Type_ID = @ID,Name = @Name" & _
            "Rate = @Rate WHERE  Service_ID = @SID"

        cmd.Parameters.AddWithValue("@ID", txtBoxTypeID.Text)
        cmd.Parameters.AddWithValue("@Name", txtBoxName.Text)
        cmd.Parameters.AddWithValue("@Rate", txtBoxRate.Text)
        cmd.Parameters.AddWithValue("@SID", txtBoxID.Text)
        cmd.ExecuteNonQuery()
        MessageBox.Show("Successfully Updated")
    Catch ex As Exception
        MessageBox.Show("Error while inserting record on table..." & ex.Message, "Update Records")
    Finally
        con.Close()
        btnSave.Show()
        txtBoxTypeID.Clear()
        txtBoxName.Clear()
        txtBoxRate.Clear()
        txtBoxID.Clear()
    End Try
End Sub

结束班