依賴組合框填充問題

Question

我有一個windows窗體和用戶從組合框中選擇布參數，如國家 - 城市 方法。和我的參數是：

typeName - typeNo - pattern - variant 
R - 125 - 254978 - 1 
R - 125 - 254979 - 1 
R - 125 - 254979 - 2 
Ri- 54 - 54658 - 1 
Ri- 54 - 54658 - 2... etc. 

我填的是typeNameCombobox上formLoad 後比typeNoCombobox填寫typeNameCombobox_SelectedIndexChanged（）事件 像這樣patternCombobox填寫typeNoCombobox_SelectedIndexChanged（）事件......

但有是typeNameCombobox_SelectedIndexChanged（） 中的一個問題，錯誤消息說：

無法綁定多部分標識符「System.Data.DataRowView」。

和一個使用這種方法荒謬

if (typeNameCombobox .SelectedValue.ToString() != "System.Data.DataRowView") 
{ 
fill -> typeNoCombobox 
} 

altought這四個組合框是依賴性的，在組合框下面的arent上冷杉負載填充。

我用第二個荒謬的方法

typeName.selectedIndex = 1; 
typeName.selectedIndex = 0; 
typeName.selectedIndex = 1; 
typeName.selectedIndex = 0; 

（我不得不做出這個最小的4倍，因爲有四個相關的組合框）

的所有組合框後填寫有，如果用戶沒有問題改變typeName所有的依賴值是changin

有沒有什麼辦法讓這段代碼清楚？響應後

編輯：

蒂普圖爾=類型名稱 尖端= typeNo 德森=圖案 varyant =變種

這裏是我的原代碼

ConnectionClassOleDb cc = new ConnectionClassOleDb(); 


    private void SiparisDetay_Load(object sender, EventArgs e) //formload 
     {    

      sorgu = "Select distinct tipTurId, tipTur from View_Tip order by tipTur"; 
      cc.cbDoldur(sorgu, cbTipTur, "tipTur", "tipTurId"); 

      cbTipTur.SelectedIndex = 1; 
      cbTipTur.SelectedIndex = 0; 
      cbTipTur.SelectedIndex = 1; 
      cbTipTur.SelectedIndex = 0;  

     } 



    private void cbTipTur_SelectedIndexChanged(object sender, EventArgs e) 
     { 
      if (cbTipTur.SelectedValue.ToString() != "System.Data.DataRowView") 
      { 
       string sorgu = "SELECT distinct tipNo FROM tblTip where " + 
        " tipTurId = '" + cbTipTur.SelectedValue.ToString() + "' ORDER BY tipNo"; 
       cc.cbDoldur(sorgu, cbTip, "tipNo", "tipNo"); 

      } 
     } 

     private void cbTip_SelectedIndexChanged(object sender, EventArgs e) 
     { 
      if (cbTip.SelectedValue.ToString() != "System.Data.DataRowView") 
      { 
       string sorgu = "SELECT desen FROM tblTip WHERE " + 
        " tipTurId = '" + cbTipTur.SelectedValue.ToString() + 
        "' AND tipNo = '" + cbTip.SelectedValue.ToString() + "' order by desen"; 
       cc.cbDoldur(sorgu, cbDesen, "desen", "desen"); 
      } 
     } 

     private void cbDesen_SelectedIndexChanged(object sender, EventArgs e) 
     { 
      if (cbDesen.SelectedValue.ToString() != "System.Data.DataRowView") 
      { 
       string sorgu = "SELECT varyant FROM tblTip WHERE " + 
           " desen = '" + cbDesen.SelectedValue.ToString() + 
           "' AND tipTurId = '" + cbTipTur.SelectedValue.ToString() + 
           "' AND tipNo = '" + cbTip.SelectedValue.ToString() + "' ORDER BY varyant"; 
       cc.cbDoldur(sorgu, cbVaryant, "varyant", "varyant"); 
      } 
     } 

和在像這樣connectionclass代碼：

public void cbDoldur(string sorgu, ComboBox cb, string text, string value) //fill combobox 
     {   
      DataTable dtDdl = Dt(sorgu); 
      cb.DataSource = dtDdl; 
      cb.DisplayMember = text; 
      cb.ValueMember = value;    

      if (cb.Items.Count > 0) 
      { 
       cb.SelectedIndex = 0; 
      } 

     } 


public DataTable Dt(string query) 
     { 

      DataTable dt = new DataTable(); 
      if (Open()) 
      { 
       OleDbDataAdapter da = new OleDbDataAdapter(query, connection); 
       try 
       { 
        da.Fill(dt); 

       } 
       catch (Exception ex) 
       { 
        MessageBox.Show("Sistem Mesajı:" + ex.Message, "Hata", MessageBoxButtons.OK, MessageBoxIcon.Error); 
       } 
      } 
      //connection.Close(); 
      return dt; 
     } 

Answer 1

我解決我的問題，以改變我的comboboxpopulate功能類這樣

cb.DisplayMember = text; 
cb.ValueMember = value; 
cb.DataSource = dtDdl; 

Answer 2

你應該嘗試添加別名在查詢的字段名的

Select distinct tipTurId, tipTur from View_Tip 

要

Select distinct tipTurId as tipTurId , tipTur from View_Tip 

，並且在這種情況下SELECT distinct tipNo FROM tblTip到

SELECT distinct tipNo as tipNo FROM tblTip 

，因爲這將無法找到域在DataSource中爲tipTurId，因爲它會以Distinct返回，與tipNo