與MS訪問的C＃連接不起作用？

Question

當我開始調試並添加一些客戶端時，我可以添加它們，更新它們並閱讀它們。但新添加的客戶端不會保存在我的數據庫中。如果我使用正確的文件的位置和我檢查了我：

public class DBaccess 
{ 

    private static string connectionstr; 

    static DBaccess() 
    { 
     string mdffile; 
     mdffile = @"C:\Users\rik\Documents\Visual Studio 2010\Projects\Week-2-Opdracht\Database\Clienten.accdb"; 

     connectionstr = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + mdffile + ";"; 

    } 

    public static DataSet Getwaardenquery(string sqlstr) 
    { 
     DataSet ds = new DataSet(); 
     Console.WriteLine(sqlstr); 
     OleDbConnection con = new OleDbConnection(connectionstr); 

     OleDbDataAdapter dap = new OleDbDataAdapter(sqlstr, con); 
     dap.Fill(ds); 
     return ds; 

    } 

    public static int Uitvoerenquery(string sqlstr) 
    { 
     int resultaat = -1; 
     Console.WriteLine(sqlstr); 

     OleDbConnection con = new OleDbConnection(connectionstr); 
     OleDbCommand cmd = new OleDbCommand(sqlstr, con); 

     try 
     { 
      con.Open(); 
      resultaat = cmd.ExecuteNonQuery(); 
     } 
     catch (Exception exp) 
     { 
      string x = exp.Message; 
     } 
     finally 
     { 
      if (con.State == ConnectionState.Open) 
      { 
       con.Close(); 
      } 
     } 
     return resultaat; 
    } 

} 
} 

Answer 1

首先檢查一下您的連接字符串的正確與否通過人工連接。 如需幫助請按照給定鏈路
http://www.c-sharpcorner.com/UploadFile/b8d90a/connect-oledb-database-in-C-Sharp-in-easy-steps/

Answer 2

你的代碼包含多餘的分號

connectionstr = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source='" + mdffile + "'"; 

語法錯誤