如何绑定绑定下拉列表 [英] how to bind bind Dropdown List

问题描述

DataTable ds = new DataTable();
            ds = select.SelectData("Sp_Erp_Pur_PRQuotationMaster_Select");
            ddl_Show.DataSource = ds;
            ddl_Show.DataTextField = "Quotation_ID";
            ddl_Show.DataValueField = "Quotation_ID";
            ddl_Show.DataBind();

这是我的绑定下拉列表代码select.selectData是我使用的我的Dll名称从sql server获取数据



此代码适用于同一个下拉列表，而不是asp.net中的其他页面

this is my code of binding dropdownlist select.selectData is my Dll Name that i used for fetching data from sql server

this code is work for same dropdownlist in one page and not for anther page in asp.net

推荐答案

DataTable dtTable = new DataTable();

        try
        {
            using (SqlConnection sqlConnection = new SqlConnection("Your connection"))
            {
                using (SqlCommand sqlCommand = new SqlCommand("Your Selection Query", sqlConnection))
                {
                    sqlConnection.Open();

                    using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                    {
                        dtTable.Load(sqlDataReader);
                        sqlDataReader.Close();
                    }
                }
            }
        }
        catch (Exception error)
        {
            throw error;
        }

        ddlList.DataSource = dtTable;
        ddlList.DataValueField = "id";
        ddlList.DataTextField = "id";
        ddlList.DataBind();

1.在ASP.NET中，用于初始化控件的事件很重要，通常是 Page_Load 使用了事件，但在某些情况下也可以 Page_Init 。有关详细信息，请参阅 ASP.NET页面生命周期概述 [< a href =http://msdn.microsoft.com/en-us/library/ms178472(v=vs.80).ASPX\"target =_ blanktitle =New Window> ^ ]



2.在您的情况下，您应该将您的代码初始化并绑定到 Page_Load 事件中的下拉列表但是仅当页面没有回发时，如下一个示例所示：

1.In ASP.NET is important the event that you use to init your controls, in generally the Page_Load event is used but could be also Page_Init in some situations. For more details see ASP.NET Page Life Cycle Overview[^]

2.In your case you should place your code that init and bind your drop down list in Page_Load event but only when the page is not post back, like in the next example:

protected void Page_Load(object sender, EventArgs e)
{
   if (!Page.IsPostBack)
   {
      //Put your code for init and binding here!
   }
}

SqlCommand cmd = new SqlCommand("SPC", new SqlConnection(ConfigurationManager.AppSettings["ConnString"]));
cmd.Connection.Open();
 
SqlDataReader ddlValues;
ddlValues = cmd.ExecuteReader();
 
DropDownList1.DataSource = ddlValues;
DropDownList1.DataValueField = "theName";
DropDownList1.DataTextField = "theName";
DropDownList1.DataBind();
 
cmd.Connection.Close();
cmd.Connection.Dispose();

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