VB.NET ASP.NET Sql Command Delete Statement Source Code Example

Posted by on Tuesday, December 15, 2009 · Leave a Comment 

Sql Command Delete Statement

Purpose: – Illustrates using in VB.NET ASP.NET.

Prerequistes:

  1. Install Visual Web Developer 2008
  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 Visual Basic for Language
    • name of Web Site could be VBNET_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.vb
  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="VB" AutoEventWireup="false" CodeFile="SqlCommandDelete.aspx.vb" 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 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:textbox>
        </td>
        </tr>
        <tr>
        <td>Last Name: </td><td>
        <asp:textbox ID="txtLastName" runat="server"></asp:textbox>
        </td>
        </tr>
        </table><br />
        <asp:button ID="btnDelete" runat="server" Text="Delete" /><br />
        <asp:label ID="lblErrMsg" runat="server" Text="lblErrMsg" ForeColor="#FF3300" 
            Visible="False"></asp:label><br />
        <asp:gridview ID="GridView1" runat="server" DataSourceID="sdsEmployees">
        </asp:gridview>
        <asp:sqldatasource ID="sdsEmployees" runat="server" 
            ConnectionString="<%$ ConnectionStrings:Northwind_ConnectionString %>" 
            SelectCommand="SELECT [FirstName], [LastName] FROM [Employees]">
        </asp:sqldatasource>
    </div>
    </form>
</body>
</html>

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

Imports System
Imports System.Data
Imports System.Data.SqlClient
 
Partial Class Database_ADONET_SqlCommandDelete
    Inherits System.Web.UI.Page
 
    Protected Sub btnDelete_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDelete.Click
        Dim thisConnection As New SqlConnection(ConfigurationManager.ConnectionStrings("Northwind_ConnectionString").ConnectionString)
 
        'Create Command object
        Dim nonqueryCommand As SqlCommand = thisConnection.CreateCommand()
 
        Try
            ' Open Connection
            thisConnection.Open()
 
            ' Create DELETE 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 ex As SqlException
            ' Display error
            lblErrMsg.Text = ex.ToString()
            lblErrMsg.Visible = True
 
        Finally
            ' Close Connection
            thisConnection.Close()
 
        End Try
        GridView1.DataBind()
    End Sub
 
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        lblErrMsg.Visible = False
 
    End Sub
End Class

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>

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