接続は有効でなければなりません。VB.netでVB.netエラーが発生しました。

Question

これはEXCELファイルのデータをODBC driverで読み込み、MySqlデータベースに書き込むコードです。

私はこのエラーを得た

Public Class WebForm3 
    Inherits System.Web.UI.Page 

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 

    End Sub 

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
     Dim MySqlCmd = New SqlCommand() 

     ' Dim dialog As New System.Windows.Forms.OpenFileDialog() 
     'Dim dialog As New OpenFileDialog() 
     'dialog.Filter = "Excel files |*.xls;*.xlsx" 
     'dialog.InitialDirectory = "C:\" 
     'dialog.Title = "Select file for import" 
     'If dialog.ShowDialog() = DialogResult.OK Then 
     Try 
      Dim dt As DataTable 
      Dim buff0 As String 
      Dim buff1 As String 
      Dim buff2 As String 

      dt = ImportExceltoDatatable("C:\\Book1.xls") 

      For i = 0 To dt.Rows.Count - 1 
       buff0 = dt.Rows(i)(0) 
       buff1 = dt.Rows(i)(1) 
       buff2 = dt.Rows(i)(2) 

       Dim connStr As String = "server=localhost;user=root;database=ajaxsamples;port=3306;password=innoera;" 
       Dim connMysql As MySqlConnection = New MySqlConnection(connStr) 
       Dim sql As String = "INSERT INTO ajaxsamples.customers VALUES('" & buff0 & "','" & buff1 & "','" & buff2 & "')" 
       Dim cmd As MySqlCommand = New MySqlCommand(sql, connMysql) 
       cmd.ExecuteNonQuery() 
       cmd.Dispose() 
       connMysql.Close() 
      Next 
     Catch ex As Exception 
      MsgBox(Err.Description, MsgBoxStyle.Critical) 
     End Try 

     'End If 
    End Sub 


    Public Shared Function ImportExceltoDatatable(filepath As String) As DataTable 
     ' string sqlquery= "Select * From [SheetName$] Where YourCondition"; 
     Dim dt As New DataTable 
     Try 
      Dim ds As New DataSet() 
      Dim constring As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & filepath & ";Extended Properties=""Excel 12.0;HDR=YES;""" 
      Dim con As New OleDbConnection(constring & "") 

      con.Open() 
      Dim myTableName = con.GetSchema("Tables").Rows(0)("TABLE_NAME") 
      Dim sqlquery As String = String.Format("SELECT * FROM [{0}]", myTableName) 
      'Dim myTableName = con.GetSchema("Tables").Rows(0)("TABLE_NAME") 
      'Dim sqlquery As String = String.Format("SELECT * FROM Sheet1$") ' "Select * From " & myTableName 

      Dim da As New OleDbDataAdapter(sqlquery, con) 
      da.Fill(ds) 

      dt = ds.Tables(0) 
      Return dt 
     Catch ex As Exception 
      MsgBox(Err.Description, MsgBoxStyle.Critical) 
      Return dt 
     End Try 
    End Function 

End Class 

、

いただきました！間違ったコード内の "接続が有効と開いていなければなりませんか"？私はVBの初心者です。どんな助けもありがとう。

Answer 1

接続を開くことを忘れました。

Try 
    connMysql = New MySqlConnection 
    connMysql.ConnectionString = connStr 
    connMysql.Open() 'You forgot to open your connection 
    sql = "SELECT * FROM users" 

    cmd = New MySqlCommand(sql, connMysql) 
    cmd.ExecuteNonQuery() 
    cmd.Dispose() 
Catch ex As Exception 
    'your error code here 
Finally 
    connMysql.Close() 'close your connection 
End Try