DataGridviewでSQL Server MDFファイルを開く

Question

私はVisual Basicを初めて使用しています。前回のVisual Basicクラスを楽しく学びました。教授が私に与えた.MDF SQL Serverデータベースファイルに接続するためにdatagridviewを取得するのに問題があります。 sConnection.ConnectionString = ""でnull例外エラーが発生していますが、私はこの問題を抱えています。

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
    sConnection.ConnectionString = "Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\Jkome\Desktop\Kayaks.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True" 
    sConnection.Open() 

    sCommand.CommandText = "Select * from KayakTypes;" 
    sReader = sCommand.ExecuteReader() 
    sTable.Load(sReader) 
    DGVkyaks.DataSource = sTable 

Answer 1

まず、

Imports System.Data.SqlClient 
Public Class Form1 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
     Dim sTable As New DataTable 
     Dim connectionString As String = 
      <Text> 
       Data Source=(LocalDB)\v11.0; 
       AttachDbFilename=C:\Users\Jkome\Desktop\CustomerDatabase.mdf; 
       Integrated Security=True; 
       Connect Timeout=30 
      </Text>.Value 

     Using cn As New SqlConnection With {.ConnectionString = connectionString} 
      Using cmd As New SqlCommand With 
       { 
        .CommandText = "Select * from KayakTypes", 
        .Connection = cn 
       } 

       cn.Open() 
       sTable.Load(cmd.ExecuteReader) 

      End Using 
     End Using 

     DGVkyaks.DataSource = sTable 

    End Sub 
End Class