C# ASP.NET Sql Command Delete Statement Source Code Example

Posted by on Wednesday, December 16, 2009 · Leave a Comment 

Sql Command Delete Statement

Purpose: – Illustrates using in C-Sharp ASP.NET.

Prerequistes:

  1. Install C# (Express or Standard Edition)
  2. Install SQL Server Express
  3. Download Northwind and Pubs Databases
  4. Attach Northwind Database to Databases in Sql Express
  5. Attach pubs 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 add new web forms to it.

Instructions:

  1. Use Visual Web Developer 2008
  2. Create new web site;
    • Click File/New Web Site
    • Select ASP.NET Website Template
    • Select C-Sharp for Language
    • name of Web Site could be CSharp_ASPNET_Syntax.
  3. Add New folder named “Database_ADONET”
    • Right-click project name in solution explorer;
    • add new folder;
    • name of folder could be: Database_ADONET
  4. Add Web Form Named SqlCommandDelete to Database_ADONET folder
    • Right-click Database_ADONET folder;
    • add new item;
    • Select Web Form
    • Check place code behind in separate file
    • Web Form name could be SqlCommandDelete
  5. Click on copy code in code below to copy code into web form SqlCommandDelete.aspx
  6. Click on copy code in second set of code below to copy code into code-behind SqlCommandDelete.aspx.cs
  7. Right-click on SqlCommandDelete.aspx in solution explorer and select view in browser

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

< %@ Page Language="C#" AutoEventWireup="false" CodeFile="SqlCommandDelete.aspx.cs" Inherits="Database_ADONET_SqlCommandDelete" %>
 
< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <table>
        <tr>
        <td>First Name: </td><td>
        <asp :TextBox ID="txtFirstName" runat="server"></asp>
        </td>
        </tr>
        <tr>
        <td>Last Name: </td><td>
        <asp :TextBox ID="txtLastName" runat="server"></asp>
        </td>
        </tr>
        </table><br />
        <asp :Button ID="btnDelete" runat="server" Text="Delete" onClick="btnDelete_Click" /><br />
        <asp :Label ID="lblErrMsg" runat="server" Text="lblErrMsg" ForeColor="#FF3300" 
            Visible="False"></asp><br />
        <asp :GridView ID="GridView1" runat="server" DataSourceID="sdsEmployees">
        </asp>
        <asp :SqlDataSource ID="sdsEmployees" runat="server" 
            ConnectionString="<%$ ConnectionStrings:Northwind_ConnectionString %>" 
            SelectCommand="SELECT [FirstName], [LastName] FROM [Employees]">
        </asp>
    </div>
    </form>
</body>
</html>

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

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
 
partial class Database_ADONET_SqlCommandDelete : System.Web.UI.Page
{
 
    protected void  btnDelete_Click(object sender, System.EventArgs e)
    {
        SqlConnection thisConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["Northwind_ConnectionString"].ConnectionString);
 
        //Create Command object
        SqlCommand nonqueryCommand = thisConnection.CreateCommand();
 
        try
        {
            // Open Connection
            thisConnection.Open();
 
            // Create INSERT statement with named parameters
            nonqueryCommand.CommandText = "DELETE Employees WHERE FirstName = @FirstName and LastName = @LastName";
 
            // Add Parameters to Command Parameters collection
            nonqueryCommand.Parameters.Add("@FirstName", SqlDbType.VarChar, 10);
            nonqueryCommand.Parameters.Add("@LastName", SqlDbType.VarChar, 20);
 
 
            nonqueryCommand.Parameters["@FirstName"].Value = txtFirstName.Text;
            nonqueryCommand.Parameters["@LastName"].Value = txtLastName.Text;
 
            nonqueryCommand.ExecuteNonQuery();
        }
 
        catch (SqlException ex)
        {
            // Display error
            lblErrMsg.Text = ex.ToString();
            lblErrMsg.Visible = true;
        }
 
        finally
        {
            // Close Connection
            thisConnection.Close();
 
        }
        GridView1.DataBind();
    }
 
    protected void Page_Load(object sender, System.EventArgs e)
    {
        lblErrMsg.Visible = false;
 
    }
}

Step 3: Click on Copy Code to Cut-n-paste code into web.config right after the appSettings section 

<connectionstrings>
    <add name="Northwind_ConnectionString"
      connectionString="Server=(local)\SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=SSPI" />
    <add name="Pubs_ConnectionString"
      connectionString="Server=(local)\SQLEXPRESS;Initial Catalog=pubs;Integrated Security=SSPI" />
  </connectionstrings>

Filed under Code Samples · Tagged with , , , , ,