從類型LINQ結果到類型'整數'的轉換無效

Question

我創建了一個帶有組合框的表單來搜索和4個文本框來查看字段值。我使用Form_load事件來填充組合框。

這裏是我的代碼：

Imports System.Data.SqlClient 
Imports System.Data.Linq 

Public Class FRM_Product 
    Dim connection As New SqlConnection(connection string) 
    Dim db As New ProductDataContext(connection) 

    Private Sub FRM_ Product_Load(sender As Object, e As EventArgs) Handles 
     MyBase.Load 
     Dim V_Query = db.Product_Write(Nothing, Nothing, Nothing, Nothing).ToList 
     If V_Query.Count <> 0 Then 
      CMB_Search.DataSource = V_Query 
      CMB_Search.ValueMember = "Product_ID" 
      CMB_Search.DisplayMember = "Product_A" 
     End If 
    End Sub 

    Private Sub CMB_Search_SelectedIndexChanged(sender As Object, e As EventArgs) Handles CMB_Search.SelectedIndexChanged 
     Dim ID As Integer = CMB_Search.SelectedValue 

     Dim V_Query = db.Product_Write(Nothing, Nothing, Nothing, Nothing).ToList 
     TXT_Product_ID.Text = V_Query(0). Product_ID 
     TXT_ Product_A.Text = V_Query(0). Product_A 
     TXT_ Product_E.Text = V_Query(0). Product_E 
     TXT_ Product_NOTE.Text = V_Query(0). Product_Note 
    End Sub 

而這裏的Product_Write存儲過程：

CREATE PROCEDURE Product_Write 
    @ Product_ID INT = NULL , 
    @ Product_A nvarchar(50)= NULL , 
    @ Product_E nvarchar(50)= NULL , 
    @ Product_Note nvarchar(255)= NULL 
AS 
    BEGIN 
     SET NOCOUNT ON; 
     BEGIN 
      SELECT * 
      FROM [dbo].[ Product] 
      WHERE [Product_ID] = ISNULL(@Product_ID,[Product_ID]) 
       AND [Product_A] = ISNULL(@Product_A,[Product_A]) 
       AND [Product_E] = ISNULL(@Product_E, [Product_E]) 
      ORDER BY [Product_A] 
     END 
    END 

線

Dim ID As Integer = CMB_Search.SelectedValue 

導致此錯誤：

Conversion from type ' Product_WriteResult' to type 'Integer' is not valid.'

如何解決此錯誤？

Answer 1

你可以試試這個：

Dim myDataRowView As DataRowView = DirectCast(CMB_Search.SelectedValue, DataRowView) 
Dim ID as Integer = CInt(myDataRowView("Product_ID"))