C# ASP.NET DropDownList Bind To Table Source Code Example

Posted by on Saturday, December 12, 2009 · Leave a Comment 

C# ASP.NET DropDownList Bind To Table Source Code Example

Purpose: – Illustrates using DropDownList and bind to data table for C# ASP.NET.
Prerequistes:

  1. Install Visual Studio 2022
  2. Watch this video to enable web forms in Visual Studio 2022 Enable Web Forms websites in Visual Studio 2022
  3. Install SQL Server Express
  4. Download Northwind Database
  5. Attach Northwind Database to Databases in Sql Express

Notes:

  • You can build your own library of syntax examples by using same web site over and over and just adding new web forms.

Instructions:

  1. Use Visual Studio 2022
  2. Create new web site;
    • Select Create New Project
    • Select ASP.NET Web Forms Site Template
    • name of project could be CSharp_ASPNET_Syntax
    • name of solution could be CSharp_ASPNET_Syntax.
  3. Add New folder named “Standard_Controls”
    • Right-click project name in solution explorer;
    • add new folder;
    • name of folder could be: Standard_Controls
  4. Add Web Form Named DropDownListBindToTable to Standard_Controls folder
    • Right-click Standard_Controls folder;
    • add new item;
    • Select Web Form
    • Check place code behind in separate file
    • Web Form name could be DropDownListBindToTable
  5. Click on copy code in code below to copy code into web form DropDownListBindToTable.aspx
  6. Click on copy code in second set of code below to copy code into code-behind DropDownListBindToTable.aspx.cs
  7. Click green arrow to start with debugging

Step 1: Click on Copy Code to Cut-n-paste code into DropDownListBindToTable.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="DropDownListBindToTable.aspx.cs" Inherits="DropDownListBindToTable" %>
    <title></title>
    <form id="form1" runat="server">
 
<div>
            <asp:dropdownlist id="DropDownList1" runat="server">
            </asp:dropdownlist>
</div>
 
    </form>

Step 2: Click on Copy Code to Cut-n-paste code into DropDownListBindToTable.aspx.cs

using System;
using System.Data;
using System.Data.SqlClient;
using System.Collections;
 
 
 
partial class DropDownListBindToTable : System.Web.UI.Page
{
    protected void // ERROR: Handles clauses are not supported in C#
    Page_Load(object sender, System.EventArgs e)
    {
        SqlConnection con = new SqlConnection("Server=(local)\\SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=SSPI");
        SqlCommand cmd = new SqlCommand();
 
        cmd.CommandText = "SELECT EmployeeID, FirstName + ' ' + LastName as FullName FROM Employees";
        cmd.Connection = con;
 
        DataTable Table1;
        Table1 = new DataTable("Employees");
        //creating a table named Employees
        DataRow Row1;
        //declaring row for the table
 
        DataColumn EmployeeID = new DataColumn("EmployeeID");
        //declaring a column named EmployeeID
        EmployeeID.DataType = System.Type.GetType("System.Int32");
        //setting the datatype for the column
        Table1.Columns.Add(EmployeeID);
        //adding the column to table
        DataColumn FullName = new DataColumn("FullName");
        FullName.DataType = System.Type.GetType("System.String");
        Table1.Columns.Add(FullName);
 
        try
        {
            con.Open();
            SqlDataReader reader = cmd.ExecuteReader();
            //(CommandBehavior.SingleRow)
            while (reader.Read())
            {
                Row1 = Table1.NewRow();
                //declaring a new row
                Row1["EmployeeID"] = reader.GetInt32(0);
                //filling the row with values. Item property is used to set the field value.
                Row1["FullName"] = reader.GetString(1);
                //filling the row with values. adding FullName
                Table1.Rows.Add(Row1);
            }
            reader.Close();
        }
        finally
        {
            con.Close();
        }
        DropDownList1.DataSource = Table1;
        this.DropDownList1.DataTextField = "FullName";
        this.DropDownList1.DataValueField = "EmployeeID";
        DropDownList1.DataBind();
    }
}

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