我们可以在C＃中绑定多个dropdownblist的数据吗？ [英] Can we bind the data for multiple dropdownblist in C#?

问题描述

我在webform中有3个下拉列表，所以我想从SQL数据库绑定数据，我能够为一个下拉列表执行此操作..如何从同一个sqldatabase绑定其他两个下拉列表的数据...



我的代码：

使用System; 
使用System.Collections.Generic; 
使用System.Linq; 
使用System.Web; 
使用System.Web.UI; 
使用System.Web.UI.WebControls; 
使用System.Data; 
使用System.Data.SqlClient; 
使用System.Configuration; 
 
命名空间Expense_System 
 {
公共部分类事务：System.Web.UI.Page 
 {
 protected void Page_Load（object sender，EventArgs e） 
 {
 
 String strConnString = ConfigurationManager.ConnectionStrings [conString]。ConnectionString; 
 
 SqlConnection con = new SqlConnection（strConnString）; 
 
 con.Open（）; 
 
 SqlCommand cmd = new SqlCommand（select * from Expense_Type，con）; 
 
 DropDownListexpensetype.DataSource = cmd.ExecuteReader（）; 
 DropDownListexpensetype.DataTextField =Expense_Type; 
 DropDownListexpensetype.DataValueField =Expense_Type; 
 DropDownListexpensetype.DataBind（）; 
 
 
 
 
} 
 
 protected void BtncreateExpense_Click（object sender，EventArgs e）
 {
 String strConnString = ConfigurationManager.ConnectionStrings [conString]。ConnectionString; 
 
 SqlConnection con = new SqlConnection（strConnString）; 
 
 con.Open（）; 
 
 SqlCommand cmd = new SqlCommand（）; 
 
 cmd.CommandType = CommandType.StoredProcedure; 
 
 cmd.CommandText =[dbo]。[Spcreatetransactions]; 
 
 cmd.Parameters.Add（@ Payee，SqlDbType.VarChar）.Value = tbpayee.Text; 
 cmd.Parameters.Add（@ Date，SqlDbType.Date）.Value = tbdate.Text; 
 cmd.Parameters.Add（@ AMOUNT，SqlDbType.Int）.Value = tbamount.Text; 
 cmd.Parameters.Add（@ expensetype，SqlDbType.VarChar）.Value = DropDownListexpensetype.Text; 
 cmd.Parameters.Add（@ person，SqlDbType.Int）.Value = DropDownListperson.Text; 
 cmd.Parameters.Add（@ card，SqlDbType.Int）.Value = DropDownListcard.Text; 
 
 cmd.Connection = con; 
 
 int totalrecords =（int）cmd.ExecuteNonQuery（）; 
 Response.Write（创建的事务数为+ totalrecords.ToString（））; 
 
 
 con.Close（）; 
 
} 
 
} 
} 

什么我试过了：



i也尝试了这样但不起作用，它抛出了unhandledexception错误。

使用System; 
使用System.Collections.Generic; 
使用System.Linq; 
使用System.Web; 
使用System.Web.UI; 
使用System.Web.UI.WebControls; 
使用System.Data; 
使用System.Data.SqlClient; 
使用System.Configuration; 
 
命名空间Expense_System 
 {
公共部分类事务：System.Web.UI.Page 
 {
 protected void Page_Load（object sender，EventArgs e） 
 {
 
 String strConnString = ConfigurationManager.ConnectionStrings [conString]。ConnectionString; 
 
 SqlConnection con = new SqlConnection（strConnString）; 
 
 con.Open（）; 
 
 SqlCommand cmd = new SqlCommand（select * from Expense_Type，con）; 
 
 DropDownListexpensetype.DataSource = cmd.ExecuteReader（）; 
 DropDownListexpensetype.DataTextField =Expense_Type; 
 DropDownListexpensetype.DataValueField =Expense_Type; 
 DropDownListexpensetype.DataBind（）; 
 
 
 SqlCommand cmd2 = new SqlCommand（select * from [dbo]。[User_details]，con）; 
 
 DropDownListperson.DataSource = cmd2.ExecuteReader（）; 
 DropDownListperson.DataTextField =Full_Name; 
 DropDownListperson.DataValueField =Full_Name; 
 DropDownListperson.DataBind（）; 
 
} 
 
 protected void BtncreateExpense_Click（object sender，EventArgs e）
 {
 String strConnString = ConfigurationManager.ConnectionStrings [conString]。ConnectionString; 
 
 SqlConnection con = new SqlConnection（strConnString）; 
 
 con.Open（）; 
 
 SqlCommand cmd = new SqlCommand（）; 
 
 cmd.CommandType = CommandType.StoredProcedure; 
 
 cmd.CommandText =[dbo]。[Spcreatetransactions]; 
 
 cmd.Parameters.Add（@ Payee，SqlDbType.VarChar）.Value = tbpayee.Text; 
 cmd.Parameters.Add（@ Date，SqlDbType.Date）.Value = tbdate.Text; 
 cmd.Parameters.Add（@ AMOUNT，SqlDbType.Int）.Value = tbamount.Text; 
 cmd.Parameters.Add（@ expensetype，SqlDbType.VarChar）.Value = DropDownListexpensetype.Text; 
 cmd.Parameters.Add（@ person，SqlDbType.Int）.Value = DropDownListperson.Text; 
 cmd.Parameters.Add（@ card，SqlDbType.Int）.Value = DropDownListcard.Text; 
 
 cmd.Connection = con; 
 
 int totalrecords =（int）cmd.ExecuteNonQuery（）; 
 Response.Write（创建的事务数为+ totalrecords.ToString（））; 
 
 
 con.Close（）; 
 
} 
 
} 
} 

解决方案

你必须告诉我们哪一行导致错误。



无论如何，试试这个：

  protected   void  Page_Load（ object  sender，EventArgs e）{
  if （！IsPostback）{
 BindAll（）; 
} 
} 
 
 私人  void  BindAll（ ）{
 BindExpenseList（）; 
 BindPersonList（）; 
} 
 
  private   string  GetConnectionString（）{
  return  ConfigurationManager.ConnectionStrings [  conString]的ConnectionString; 
} 
 
 
  private   void  BindExpenseList（） {
 使用（SqlConnection con =  new  SqlConnection（GetConnectionString（）））{
 使用（SqlCommand cmd =  new  SqlCommand（  select * from Expense_Type，con））{
 con.Open（）; 
 DropDownListexpensetype.DataSource = cmd.ExecuteReader（）; 
 DropDownListexpensetype.DataTextField =   Expense_Type; 
 DropDownListexpensetype.DataValueField =   Expense_Type; 
 DropDownListexpensetype.DataBind（）; 
} 
} 
} 
 
  private   void  BindPersonList（）{
 使用（SqlConnection con =  new  SqlConnection（GetConnectionString（） ））{
 使用（SqlCommand cmd =  new  SqlCommand（  select * from [dbo]。[User_details]，con））{
 con.Open（）; 
 DropDownListperson.DataSource = cmd.ExecuteReader（）; 
 DropDownListperson.DataTextField =   Full_Name; 
 DropDownListperson.DataValueField =   Full_Name; 
 DropDownListperson.DataBind（）; 
} 
} 
} 

想法是在单独的方法中解耦每个绑定您可以轻松维护代码。

https://www.c-sharpcorner.com/UploadFile/d1558d/working-with-multiple-dropdownlist-using-Asp-Net/

I am having 3 dropdownlist in a webform so i want to bind the data from SQL database, i am able to do it for one dropdownlist.. how to bind the data for other two dropdownlist from same sqldatabase...

my code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace Expense_System
{
    public partial class Transactions : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

            String strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;

            SqlConnection con = new SqlConnection(strConnString);

            con.Open();

            SqlCommand cmd = new SqlCommand("select * from Expense_Type",con);

            DropDownListexpensetype.DataSource = cmd.ExecuteReader();
            DropDownListexpensetype.DataTextField = "Expense_Type";
            DropDownListexpensetype.DataValueField = "Expense_Type";
            DropDownListexpensetype.DataBind();


          

        }

        protected void BtncreateExpense_Click(object sender, EventArgs e)
        {
            String strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;

            SqlConnection con = new SqlConnection(strConnString);

            con.Open();

            SqlCommand cmd = new SqlCommand();

            cmd.CommandType = CommandType.StoredProcedure;

            cmd.CommandText = "[dbo].[Spcreatetransactions]";

            cmd.Parameters.Add("@Payee", SqlDbType.VarChar).Value = tbpayee.Text;
            cmd.Parameters.Add("@Date", SqlDbType.Date).Value = tbdate.Text;
            cmd.Parameters.Add("@AMOUNT", SqlDbType.Int).Value = tbamount.Text;
            cmd.Parameters.Add("@expensetype", SqlDbType.VarChar).Value = DropDownListexpensetype.Text;
            cmd.Parameters.Add("@person ", SqlDbType.Int).Value = DropDownListperson.Text;
            cmd.Parameters.Add("@card ", SqlDbType.Int).Value = DropDownListcard.Text;

            cmd.Connection = con;

            int totalrecords = (int)cmd.ExecuteNonQuery();
            Response.Write("The number of created transactions is" + totalrecords.ToString());


            con.Close();

        }

    }
}

What I have tried:

i have tried like this also but not working, it was throwing unhandledexception error.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace Expense_System
{
    public partial class Transactions : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

            String strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;

            SqlConnection con = new SqlConnection(strConnString);

            con.Open();

            SqlCommand cmd = new SqlCommand("select * from Expense_Type",con);

            DropDownListexpensetype.DataSource = cmd.ExecuteReader();
            DropDownListexpensetype.DataTextField = "Expense_Type";
            DropDownListexpensetype.DataValueField = "Expense_Type";
            DropDownListexpensetype.DataBind();


            SqlCommand cmd2 = new SqlCommand("select * from [dbo].[User_details]", con);

            DropDownListperson.DataSource = cmd2.ExecuteReader();
            DropDownListperson.DataTextField = "Full_Name";
            DropDownListperson.DataValueField = "Full_Name";
            DropDownListperson.DataBind();

        }

        protected void BtncreateExpense_Click(object sender, EventArgs e)
        {
            String strConnString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;

            SqlConnection con = new SqlConnection(strConnString);

            con.Open();

            SqlCommand cmd = new SqlCommand();

            cmd.CommandType = CommandType.StoredProcedure;

            cmd.CommandText = "[dbo].[Spcreatetransactions]";

            cmd.Parameters.Add("@Payee", SqlDbType.VarChar).Value = tbpayee.Text;
            cmd.Parameters.Add("@Date", SqlDbType.Date).Value = tbdate.Text;
            cmd.Parameters.Add("@AMOUNT", SqlDbType.Int).Value = tbamount.Text;
            cmd.Parameters.Add("@expensetype", SqlDbType.VarChar).Value = DropDownListexpensetype.Text;
            cmd.Parameters.Add("@person ", SqlDbType.Int).Value = DropDownListperson.Text;
            cmd.Parameters.Add("@card ", SqlDbType.Int).Value = DropDownListcard.Text;

            cmd.Connection = con;

            int totalrecords = (int)cmd.ExecuteNonQuery();
            Response.Write("The number of created transactions is" + totalrecords.ToString());


            con.Close();

        }

    }
}

解决方案

You have to tell us which line causes the error.

Anyway, try this instead:

protected void Page_Load(object sender, EventArgs e){
       if(!IsPostback){
	      BindAll();
       }  
	}
	
	private void BindAll(){
		BindExpenseList();
		BindPersonList();
	}
	
	private string GetConnectionString(){
		return ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
	}


	private void BindExpenseList(){
            using(SqlConnection con = new SqlConnection(GetConnectionString())){
            	using(SqlCommand cmd = new SqlCommand("select * from Expense_Type", con)){
			        con.Open();
            		DropDownListexpensetype.DataSource = cmd.ExecuteReader();
            		DropDownListexpensetype.DataTextField = "Expense_Type";
            		DropDownListexpensetype.DataValueField = "Expense_Type";
            		DropDownListexpensetype.DataBind();
	    	}
	    }
    }
	
	private void BindPersonList(){
            using(SqlConnection con = new SqlConnection(GetConnectionString())){
            	using(SqlCommand cmd = new SqlCommand("select * from [dbo].[User_details]", con)){
			        con.Open();
            		DropDownListperson.DataSource = cmd.ExecuteReader();
                    DropDownListperson.DataTextField = "Full_Name";
                    DropDownListperson.DataValueField = "Full_Name";
                    DropDownListperson.DataBind();
	    	}
	    }
    }

The idea is to decouple each binding in a separate method for you to easily maintain the code.

https://www.c-sharpcorner.com/UploadFile/d1558d/working-with-multiple-dropdownlist-using-Asp-Net/

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