Insert, update and delete (C#) : SqlServer « ADO.net Database « ASP.NET Tutorial

File: Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="AuthorManager" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <div>
      <br />
      <asp:Label id="Label1" runat="server">Select Author:</asp:Label>
      <asp:DropDownList id="lstAuthor" runat="server" AutoPostBack="True" onselectedindexchanged="lstAuthor_SelectedIndexChanged"></asp:DropDownList>&nbsp;&nbsp;&nbsp;
      <asp:Button id="cmdUpdate" runat="server" Text="Update" onclick="cmdUpdate_Click"></asp:Button>&nbsp;
      <asp:Button id="cmdDelete" runat="server" Text="Delete" onclick="cmdDelete_Click"></asp:Button>
      <br />
      <asp:Label id="Label11" runat="server" Width="99px" Height="19px">Or:</asp:Label>
      <asp:Button id="cmdNew" runat="server" Width="91px" Height="24px" Text="Create New" onclick="cmdNew_Click"></asp:Button>&nbsp;
      <asp:Button id="cmdInsert" runat="server" Width="85px" Height="24px" Text="Insert New" onclick="cmdInsert_Click"></asp:Button>
    </div>
    <br />
    <div>
      <asp:Label id="Label10" runat="server" Width="100px">Unique ID:</asp:Label>
      <asp:TextBox id="txtID" runat="server" Width="184px"></asp:TextBox>&nbsp; 
      (required:&nbsp;###-##-#### form)<br />
      
      <asp:Label id="Label2" runat="server" Width="100px">First Name:</asp:Label>
      <asp:TextBox id="txtFirstName" runat="server" Width="184px"></asp:TextBox><br />
      
      <asp:Label id="Label3" runat="server" Width="100px">Last Name:</asp:Label>
      <asp:TextBox id="txtLastName" runat="server" Width="183px"></asp:TextBox><br />
      
      <asp:Label id="Label4" runat="server" Width="100px">Phone:</asp:Label>
      <asp:TextBox id="txtPhone" runat="server" Width="183px"></asp:TextBox><br />
      
      <asp:Label id="Label5" runat="server" Width="100px">Address:</asp:Label>
      <asp:TextBox id="txtAddress" runat="server" Width="183px"></asp:TextBox><br />
      
      <asp:Label id="Label6" runat="server" Width="100px">City:</asp:Label>
      <asp:TextBox id="txtCity" runat="server" Width="184px"></asp:TextBox><br />
      
      <asp:Label id="Label7" runat="server" Width="100px">State:</asp:Label>
      <asp:TextBox id="txtState" runat="server" Width="184px"></asp:TextBox><br />
      
      <asp:Label id="Label9" runat="server" Width="100px">Zip Code:</asp:Label>
      <asp:TextBox id="txtZip" runat="server" Width="184px"></asp:TextBox>&nbsp; 
      (required: any five&nbsp;digits)<br />
      <br />
      
      <asp:Label id="Label8" runat="server" Width="93px" Height="19px">Contract:</asp:Label>&nbsp;
      <asp:CheckBox id="chkContract" runat="server"></asp:CheckBox><br />
      <br />
      
      <asp:Label id="lblResults" runat="server" Width="575px" Height="121px" Font-Bold="True"></asp:Label>
    </div>
    </div>
    </form>
</body>
</html>

File: Default.aspx.cs


using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Web.Configuration;
using System.Data.SqlClient;

public partial class AuthorManager : System.Web.UI.Page
{
    private string connectionString = WebConfigurationManager.ConnectionStrings["Pubs"].ConnectionString;


    protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            FillAuthorList();
        }
    }

    private void FillAuthorList()
    {
        lstAuthor.Items.Clear();
        string selectSQL = "SELECT au_lname, au_fname, au_id FROM Authors";

        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand(selectSQL, con);
        SqlDataReader reader;

        try
        {
            con.Open();
            reader = cmd.ExecuteReader();
            while (reader.Read())
            {
                ListItem newItem = new ListItem();
                newItem.Text = reader["au_lname"] + ", " + reader["au_fname"];
                newItem.Value = reader["au_id"].ToString();
                lstAuthor.Items.Add(newItem);
            }
            reader.Close();
        }
        catch (Exception err)
        {
            lblResults.Text = "Error reading list of names. ";
            lblResults.Text += err.Message;
        }
        finally
        {
            con.Close();
        }
    }

    protected void lstAuthor_SelectedIndexChanged(object sender, EventArgs e)
    {
        string selectSQL;
        selectSQL = "SELECT * FROM Authors ";
        selectSQL += "WHERE au_id='" + lstAuthor.SelectedItem.Value + "'";
        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand(selectSQL, con);
        SqlDataReader reader;

        try
        {
            con.Open();
            reader = cmd.ExecuteReader();
            reader.Read();

            txtID.Text = reader["au_id"].ToString();
            txtFirstName.Text = reader["au_fname"].ToString();
            txtLastName.Text = reader["au_lname"].ToString();
            txtPhone.Text = reader["phone"].ToString();
            txtAddress.Text = reader["address"].ToString();
            txtCity.Text = reader["city"].ToString();
            txtState.Text = reader["state"].ToString();
            txtZip.Text = reader["zip"].ToString();
            chkContract.Checked = (bool)reader["contract"];
            reader.Close();
            lblResults.Text = "";
        }
        catch (Exception err)
        {
            lblResults.Text = "Error getting author. ";
            lblResults.Text += err.Message;
        }
        finally
        {
            con.Close();
        }

    }
    protected void cmdNew_Click(object sender, EventArgs e)
    {
        txtID.Text = "";
        txtFirstName.Text = "";
        txtLastName.Text = "";
        txtPhone.Text = "";
        txtAddress.Text = "";
        txtCity.Text = "";
        txtState.Text = "";
        txtZip.Text = "";
        chkContract.Checked = false;
        
        lblResults.Text = "Click Insert New to add the completed record.";


    }
    protected void cmdInsert_Click(object sender, EventArgs e)
    {
        if (txtID.Text == "" || txtFirstName.Text == "" || txtLastName.Text == "")
        {
            lblResults.Text = "Records require an ID, first name, and last name.";
            return;
        }
        string insertSQL;
        insertSQL = "INSERT INTO Authors (";
        insertSQL += "au_id, au_fname, au_lname, ";
        insertSQL += "phone, address, city, state, zip, contract) ";
        insertSQL += "VALUES (";
        insertSQL += "@au_id, @au_fname, @au_lname, ";
        insertSQL += "@phone, @address, @city, @state, @zip, @contract)";

        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand(insertSQL, con);

        cmd.Parameters.AddWithValue("@au_id", txtID.Text);
        cmd.Parameters.AddWithValue("@au_fname", txtFirstName.Text);
        cmd.Parameters.AddWithValue("@au_Lname", txtLastName.Text);
        cmd.Parameters.AddWithValue("@phone", txtPhone.Text);
        cmd.Parameters.AddWithValue("@address", txtAddress.Text);
        cmd.Parameters.AddWithValue("@city", txtCity.Text);
        cmd.Parameters.AddWithValue("@state", txtState.Text);
        cmd.Parameters.AddWithValue("@zip", txtZip.Text);
        cmd.Parameters.AddWithValue("@contract", Convert.ToInt16(chkContract.Checked));

        int added = 0;
        try
        {
            con.Open();
            added = cmd.ExecuteNonQuery();
            lblResults.Text = added.ToString() + " record inserted.";
        }
        catch (Exception err)
        {
            lblResults.Text = "Error inserting record. ";
            lblResults.Text += err.Message;
        }
        finally
        {
            con.Close();
        }

        if (added > 0)
        {
            FillAuthorList();
        }
    }

    protected void cmdUpdate_Click(object sender, EventArgs e)
    {
        string updateSQL;
        updateSQL = "UPDATE Authors SET ";
        updateSQL += "au_fname=@au_fname, au_lname=@au_lname, ";
        updateSQL += "phone=@phone, address=@address, city=@city, state=@state, ";
        updateSQL += "zip=@zip, contract=@contract ";
        updateSQL += "WHERE au_id=@au_id_original";

        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand(updateSQL, con);

        cmd.Parameters.AddWithValue("@au_fname", txtFirstName.Text);
        cmd.Parameters.AddWithValue("@au_Lname", txtLastName.Text);
        cmd.Parameters.AddWithValue("@phone", txtPhone.Text);
        cmd.Parameters.AddWithValue("@address", txtAddress.Text);
        cmd.Parameters.AddWithValue("@city", txtCity.Text);
        cmd.Parameters.AddWithValue("@state", txtState.Text);
        cmd.Parameters.AddWithValue("@zip", txtZip.Text);
        cmd.Parameters.AddWithValue("@contract", Convert.ToInt16(chkContract.Checked));
        cmd.Parameters.AddWithValue("@au_id_original", lstAuthor.SelectedItem.Value);

        int updated = 0;
        try
        {
            con.Open();
            updated = cmd.ExecuteNonQuery();
            lblResults.Text = updated.ToString() + " record updated.";
        }
        catch (Exception err)
        {
            lblResults.Text = "Error updating author. ";
            lblResults.Text += err.Message;
        }
        finally
        {
            con.Close();
        }

        if (updated > 0)
        {
            FillAuthorList();
        }

    }
    protected void cmdDelete_Click(object sender, EventArgs e)
    {
        string deleteSQL;
        deleteSQL = "DELETE FROM Authors ";
        deleteSQL += "WHERE au_id=@au_id";

        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand(deleteSQL, con);
        cmd.Parameters.AddWithValue("@au_id ", lstAuthor.SelectedItem.Value);

        int deleted = 0;
        try
        {
            con.Open();
            deleted = cmd.ExecuteNonQuery();
            lblResults.Text = "Record deleted.";
        }
        catch (Exception err)
        {
            lblResults.Text = "Error deleting author. ";
            lblResults.Text += err.Message;
        }
        finally
        {
            con.Close();
        }
        if (deleted > 0)
        {
            FillAuthorList();
        }
    }
}


File: Web.config

<?xml version="1.0"?>
<configuration>
  <connectionStrings>
    <add name="Pubs" connectionString="Data Source=localhost\SQLEXPRESS;Initial Catalog=Pubs;Integrated Security=SSPI"/>
  </connectionStrings>
</configuration>
18.42.SqlServer
	18.42.1.	Connect to SQL server with integrated Authentication or SQL Authentication
	18.42.2.	Execute delete command with SqlCommand against SqlServer
	18.42.3.	You can connect to a Local database named MyLocalData.mdf by using the following connection string:
	18.42.4.	For example, the following connection string enables you to connect to a Server database named MyData:
	18.42.5.	You use SQLCMD by opening a command prompt and connecting to your database with the following command:
	18.42.6.	Read data from SQL server and fill asp:dropdownlist (C#)
	18.42.7.	Handle table relationship (C#)
	18.42.8.	Insert, update and delete (C#)