依賴組合框填充問題

Question

我有一個Windows窗體，用戶可以從組合框（如country-state-city方法）中選擇布料參數。 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.

我在typeNoCombobox填充typeNameCombobox_SelectedIndexChanged（）事件之后填充formLoad上的typeNameCombobox，並像此patternCombobox填充typeNoCombobox_SelectedIndexChanged（）事件一樣...

但是typeNameCombobox_SelectedIndexChanged（）中存在問題，錯誤消息指出：

無法綁定多部分標識符“ System.Data.DataRowView”。

並使用這種荒謬的方法

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

雖然這四個組合框是依賴的，但以下兩個組合框會填充第一個負載。

我使用第二種荒謬的方法

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

（我必須使這個最小值達到4倍，因為有四個相關的組合框）

在所有組合框填充后，如果用戶更改typeName所有相關值都已更改，則沒有問題

有什么辦法可以使這段代碼清楚嗎？

回應后編輯：

tipTur =類型名稱tip =類型否desen =模式變量=變體

這是我的原始代碼

 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");
            }
        }

和連接類中的代碼是這樣的：

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

您應該嘗試將Alias添加到查詢中的字段名稱中

Select distinct tipTurId, tipTur from View_Tip

至

Select distinct tipTurId as tipTurId , tipTur from View_Tip

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

SELECT distinct tipNo as tipNo FROM tblTip

因為因為它將以Distinct返回，所以將無法在DataSource中找到字段為tipTurId ，而tipNo的情況tipNo

Answer 2

我解決了在這樣的類中更改我的comboboxpopulate函數的問題

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