連接到SQL數據庫

Question

我正在嘗試從數據庫檢索數據到datagridview，但出現異常，

ConnectionString屬性尚未初始化。

using (conn = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=""C:\Users\BOB\Documents\Visual Studio 2012\Projects\Login\Login\Student_Marks.mdf"";Integrated Security=True"));
{
     using (adap = new SqlDataAdapter("select * from tbl_Students_Marks", conn))
     {
          DataSet das = new DataSet();
          adap.Fill(das);
          dataGridView1.DataSource = ds.Tables[0];
     }
}

Answer 1

我看到您的代碼，發現您放置了“;” 在您啟動conn的第一個using語句的末尾

using (conn = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=""C:\Users\BOB\Documents\Visual Studio 2012\Projects\Login\Login\Student_Marks.mdf"";Integrated Security=True"))//; this was the issue
{
     using (adap = new SqlDataAdapter("select * from tbl_Students_Marks", conn))
     {
          DataSet das = new DataSet();
          adap.Fill(das);
          dataGridView1.DataSource = das.Tables[0];//this must be das not ds
     }
}