Hello, the delete command operate with this:
[code]
DELETE FROM Catalogue WHERE [code] LIKE 'examplevalue'
[/code]
The above operate with one value-name of field in database.
I want to delete according value from a dropdown list (id)but there is a problem(cannot see it).Thanks
[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.SqlClient;
using System.Web.UI.HtmlControls;
using System.Configuration;
using System.Collections;
namespace WebApplication21
{
public partial class WebForm2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
SqlConnection MyConn;
SqlCommand MyCmd;
SqlDataReader MyRdr;
String MyString = "Data Source= .\\SQLEXPRESS; AttachDbFilename=|DataDirectory|\\Databasebest.mdf; Integrated Security=true; User Instance=true";
MyConn = new SqlConnection(MyString);
if (!IsPostBack)
{
MyConn.Open();
MyCmd = new SqlCommand("SELECT * FROM Catalogue", MyConn);
MyRdr = MyCmd.ExecuteReader();
DropDownList1.DataSource = MyRdr;
DropDownList1.DataValueField = "Price";
DropDownList1.DataTextField = "Code";
DropDownList1.DataBind();
MyRdr.Close();
}
}
protected void rebind()
{
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection MyConn;
SqlCommand MyCmd;
SqlDataReader MyRdr;
String MyString = "Data Source= .\\SQLEXPRESS; AttachDbFilename=|DataDirectory|\\Databasebest.mdf; Integrated Security=true; User Instance=true";
MyConn = new SqlConnection(MyString);
MyCmd = new SqlCommand("SELECT * FROM Catalogue WHERE [Code] LIKE @Code", MyConn);
MyCmd.Parameters.AddWithValue("@Code", DropDownList1.SelectedItem.Value);
MyConn.Open();
MyRdr = MyCmd.ExecuteReader();
while (MyRdr.Read())
{
product_NamTB.Text = (string)MyRdr["Product_Name"];
pricTB.Text = (string)MyRdr["Price"];
}
MyRdr.Close();
MyConn.Close();
}
protected void Button1_Click(object sender, EventArgs e)
{
SqlConnection MyConn;
SqlCommand MyCmd;
String MyString = "Data Source= .\\SQLEXPRESS; AttachDbFilename=|DataDirectory|\\Databasebest.mdf; Integrated Security=true; User Instance=true";
MyConn = new SqlConnection(MyString);
MyCmd = new SqlCommand("INSERT INTO Catalogue (Product_Name, Code, Price) VALUES (@Product_Name, @Code, @Price)", MyConn);
// update the command with the parameters from the text box’s
MyCmd.Parameters.AddWithValue("@product_Name", product_NameTB.Text);
MyCmd.Parameters.AddWithValue("@Code", CodeTB.Text);
MyCmd.Parameters.AddWithValue("@Price", PriceTB.Text);
MyConn.Open(); // open the connection
// run the query, this method is used as it does not return a value
MyCmd.ExecuteNonQuery();
MyConn.Close(); // close the connection
}
protected void Button2_Click(object sender, EventArgs e)
{
SqlConnection MyConn;
SqlCommand MyCmd;
String MyString = "Data Source= .\\SQLEXPRESS; AttachDbFilename=|DataDirectory|\\Databasebest.mdf; Integrated Security=true; User Instance=true";
MyConn = new SqlConnection(MyString);
MyCmd = new SqlCommand("UPDATE Catalogue SET [Product_Name] =@Product_Name, [Price] =@Price WHERE Code LIKE @Code", MyConn);
MyCmd.Parameters.AddWithValue("@code", DropDownList1.SelectedItem.Value);
MyCmd.Parameters.AddWithValue("@Product_Name", product_NamTB.Text);
MyCmd.Parameters.AddWithValue("@Price", pricTB.Text);
MyConn.Open();
MyCmd.ExecuteNonQuery();
MyConn.Close();
Response.Redirect("WebForm2.aspx");
}
protected void Button3_Click(object sender, EventArgs e)
{
SqlConnection MyConn;
SqlCommand MyCmd;
String MyString = "Data Source= .\\SQLEXPRESS; AttachDbFilename=|DataDirectory|\\Databasebest.mdf; Integrated Security=true; User Instance=true";
MyConn = new SqlConnection(MyString);
MyCmd = new SqlCommand("DELETE FROM Catalogue WHERE [code] LIKE @Code ", MyConn);
MyCmd.Parameters.AddWithValue("@code", DropDownList1.SelectedItem.Value);
MyConn.Open();
// run the query, this method is used as it does not return a value
MyCmd.ExecuteNonQuery();
MyConn.Close();
}
}
}
[/code]
and
[code]
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm2.aspx.cs" Inherits="WebApplication21.WebForm2" %>
<!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>
Product_Name
<asp:TextBox ID="product_NameTB" runat="server" >
</asp:TextBox>
Code
<asp:TextBox ID="CodeTB" runat="server" >
</asp:TextBox>
Price
<asp:TextBox ID="PriceTB" runat="server" >
</asp:TextBox>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Add" />
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
Product_Name
<asp:TextBox ID="product_NamTB" runat="server"></asp:TextBox>
Price
<asp:TextBox ID="pricTB" runat="server"></asp:TextBox>
<asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="Update" />
<asp:Button ID="Button3" runat="server" OnClick="Button3_Click" Text="Delete" />
</div>
</form>
</body>
</html>
[/code]