为什么我得到这个功能的错误 [英] why i getting error for this function

问题描述

protected void BindGridview（）

{

con.Open（）;



string sponcor = SELECT sponcorid FROM Registration_Master;

的SqlCommand COM =新的SqlCommand（sponcor，CON）;

com.CommandType = CommandType.Text;

SqlDataAdapter的DA =新的SqlDataAdapter（COM）;

的DataTable dtsponcor =新数据表（）;

da.Fill（dtsponcor）;

<无线电通信/>
DropDownList ddl = new DropDownList（）;



ddl = dtsponcor.Rows [0] [sponcorid];



con.Close（）;

ddl.DataSource = dtsponcor;

ddl.DataTextField =sponcorid;

ddl.DataValueField =sponcorid;

ddl.DataBind（）;

ddl.Items.Insert（0，new ListItem（ - Select- - ，0））;


}

//错误：

//错误4无法将类型''对象'隐式转换为'' System.Web.UI.WebControls.DropDownList'。 //存在显式转换（你是否错过了演员？）



//解决方案是什么？

protected void BindGridview()
{
con.Open();

string sponcor = "SELECT sponcorid FROM Registration_Master";
SqlCommand com = new SqlCommand(sponcor, con);
com.CommandType = CommandType.Text;
SqlDataAdapter da = new SqlDataAdapter(com);
DataTable dtsponcor = new DataTable();
da.Fill(dtsponcor);

DropDownList ddl = new DropDownList();

ddl = dtsponcor.Rows[0]["sponcorid"];

con.Close();
ddl.DataSource = dtsponcor;
ddl.DataTextField = "sponcorid";
ddl.DataValueField = "sponcorid";
ddl.DataBind();
ddl.Items.Insert(0, new ListItem("--Select--", "0"));

}
//Error :
//Error 4 Cannot implicitly convert type ''object'' to ''System.Web.UI.WebControls.DropDownList''. //An explicit conversion exists (are you missing a cast?)

//what is the solution for that??

推荐答案

使用此代码：

Go with this code:

protected void BindGridview()
    {
         con.Open();
 
                string sponcor = "SELECT sponcorid FROM Registration_Master";
               SqlCommand com = new SqlCommand(sponcor, con);
                com.CommandType = CommandType.Text;
               SqlDataAdapter da = new SqlDataAdapter(com);
                DataTable dtsponcor = new DataTable();
                da.Fill(dtsponcor);
 
                DropDownList ddl = new DropDownList();
 
                ddl = dtsponcor.Rows[0]["sponcorid"];

            
             con.Close();
            ddl.DataSource = dtsponcor;
            ddl.DataTextField = "sponcorid";
            ddl.DataValueField = "sponcorid";
            ddl.DataBind();
            ddl.Items.Insert(0, new ListItem("--Select--", "0"));
 
    }

您收到该错误，因为您 String 到 DropdownList ......那是不可能的......好的，所以我在这里解决了你的问题：）

You''re getting that error, because you were String to DropdownList... And that is not possible.. Okay, so here I have solved your problem :)

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