選擇在UI中檢查的列時，無法在數據庫表中找到'id'值（複選框）

Question

請幫忙。這是我爲公司的客戶服務團隊工作了大約6周的用戶界面，他們很想使用它。

與標題一樣，我試圖選擇與包含複選框的行關聯的「ID」值。如果該複選框是'checked'，我想要一個select語句運行並從該行獲取'ID'值。

protected void UpdateSelectedRecords() 
{ 
    string strPerSignStart = "%"; 
    string strPerSignEnd = "%"; 
    string strDbSearch = strPerSignStart + ddlDatabasesUpdateTCID.Text +  strPerSignEnd; 
    object NewTCID = txtTargetCID.Text; 

    DateTime curtstmp = DateTime.Now; 

    foreach (GridViewRow row in GridView1.Rows) 
    { 
    if (row.RowType == DataControlRowType.DataRow) 
    { 
     chkBox = (row.Cells[0].Controls[0] as CheckBox); 

     if (chkBox != null && Convert.ToBoolean(chkBox.Checked) == true) 
     { 
     OdbcConnection Postgreconnect2 = new OdbcConnection("Driver= {PostgreSQL Unicode};Server=localhost;Port=5433;Database=postgres;Uid=xxx;Pwd=xxx"); 

     Postgreconnect2.Open(); 

     OdbcCommand cmd = new OdbcCommand("SELECT id FROM conceptidmapping WHERE database ILIKE " + "?" + " AND " + (chkBox.Checked == true) + " ORDER BY id ASC", Postgreconnect2); 
     cmd.Parameters.AddWithValue("@database", strDbSearch); 
     cmd.Parameters["@database"].Value = Convert.ToString(strDbSearch); 
     cmd.Connection = Postgreconnect2; 
     string idVal = (string)cmd.ExecuteScalar(); 


     OdbcCommand cmd1 = new OdbcCommand("UPDATE conceptidmapping SET selected = true WHERE database ILIKE " + "?" + " AND id = " + idVal, Postgreconnect2); 
     cmd1.Parameters.AddWithValue("@database", strDbSearch); 
     cmd1.Parameters["@database"].Value = Convert.ToString(strDbSearch); 
     cmd1.Connection = Postgreconnect2; 
     cmd1.ExecuteNonQuery(); 
     } 
     } 
    } 
    } 

Answer 1

GridViews非常擅長顯示和管理數據。您聲明您擁有「與」「行關聯的」ID「值。但你不知道，你實際上做了一個數據庫調用以後檢索ID

對我來說這個尖叫「DataKey」。就我個人而言，我會找到一種方法來使您需要的ID的一部分填充GridView的數據集，然後將該ID添加爲GridView DataKey。這是您將ID與GridViewRow關聯的方式。這可以讓你消除選擇數據庫調用UpdateSelectedRecords()

但是，有時候你沒有這個選項，所以這裏是你的代碼，用這兩種解決方案修改和評論一些事情，供您考慮。

protected void UpdateSelectedRecords() 
{ 
    //////////////////////////////////////////// 
    // Since these are all local to the function 
    // 
    string strPerSignStart = "%"; 
    string strPerSignEnd = "%"; 
    string strDbSearch = strPerSignStart + ddlDatabasesUpdateTCID.Text + strPerSignEnd; 
    // 
    ////////////////////////////////////////////// 
    // Consider : 
    string strDbSearch = String.Format("%{0}%", ddlDatabasesUpdateTCID.Text); 


    ////////////////////////////////////////////// 
    // FYI These are never used 
    // 
    object NewTCID = txtTargetCID.Text; 
    DateTime curtstmp = DateTime.Now; 

    ////////////////////////////////////////////// 
    // Instantiate and open a connection once 
    // also consider using the using() statement 
    // it make managing connections much easier 
    // 
    using(OdbcConnection Postgreconnect2 = new OdbcConnection("Driver= {PostgreSQL Unicode};Server=localhost;Port=5433;Database=postgres;Uid=xxx;Pwd=xxx")); 
    { 
    Postgreconnect2.Open(); 

    // Instantiate commands once 
    OdbcCommand cmd = new OdbcCommand("", Postgreconnect2); 
    OdbcCommand cmd1 = new OdbcCommand("", Postgreconnect2); 

    foreach (GridViewRow row in GridView1.Rows) 
    { 
     if (row.RowType == DataControlRowType.DataRow) 
     { 
     chkBox = (row.Cells[0].Controls[0] as CheckBox); 

     ////////////////////////////////// 
     // chkBox.Checked *is* a boolean value, no need to convert to Bool 
     // 
     if (chkBox != null && chkBox.Checked) 
     { 
      ////////////////////////////////// 
      // Since strDbSearch doesn't change 
      // just make it part of the select string you are building 
      // This eliminates the need for parameter passing 
      // 
      // Also, check the string you are building 
      // It doesn't look like it builds a proper SELECT statement 
      // You're missing a field after "AND" 
      cmd.CommandText = 
       "SELECT id FROM conceptidmapping " 
       "WHERE database ILIKE " + strDbSearch + " AND " + 
       (chkBox.Checked == true) + " ORDER BY id ASC"; 

      ////////////////////////////////// 
      // No parameters necessary, but... 
      // This already assigns the value to the parameter 
      // 
      //cmd.Parameters.AddWithValue("@database", strDbSearch); 
      // 
      // So there is no need to do it again here 
      // 
      //cmd.Parameters["@database"].Value = Convert.ToString(strDbSearch); 


      string idVal = (string)cmd.ExecuteScalar(); 

      /////////////////////////////////// 
      // IF YOU ARE ABLE TO MAKE THE ID A DATAKEY 
      // Then the entire cmd for the select call above 
      // can be removed in favor of this: 
      // 
      string idVal = Gridview1.DataKeys(row.RowIndex).Values("id") 

      cmd1.CommandText = "UPDATE conceptidmapping SET selected = true WHERE database ILIKE " + strDBSearch + " AND id = " + idVal ; 

      cmd1.ExecuteNonQuery(); 
     } 
     } 
    } 
    } 
} 

同上面的代碼沒有註釋，並用datakey做

protected void UpdateSelectedRecords() 
{ 
    string strDbSearch = String.Format("%{0}%", ddlDatabasesUpdateTCID.Text); 

    using(OdbcConnection Postgreconnect2 = new OdbcConnection("Driver= {PostgreSQL Unicode};Server=localhost;Port=5433;Database=postgres;Uid=xxx;Pwd=xxx")); 
    { 
    Postgreconnect2.Open(); 
    OdbcCommand cmd1 = new OdbcCommand("", Postgreconnect2); 

    foreach (GridViewRow row in GridView1.Rows) 
    { 
     if (row.RowType == DataControlRowType.DataRow) 
     { 
     chkBox = (row.Cells[0].Controls[0] as CheckBox); 
     if (chkBox != null && chkBox.Checked) 
     { 
      string idVal = Gridview1.DataKeys(row.RowIndex).Values("id"); 

      cmd1.CommandText = String.Format("UPDATE conceptidmapping SET selected = true WHERE database ILIKE {0} AND id = {1}", strDbSearch, idVal) ; 
      cmd1.ExecuteNonQuery(); 
     } 
     } 
    } 
    } 
}