ASP.NET Checkbox Sample Code | How to user Checkbox?


CheckBoxList.aspx (UI)

 <body>
    <form id="form1" runat="server">

    <h2>
        Welcome to Hotel Customer’s Choice
    </h2>

    <table style="width:600px;border-color:Green;border-width:thick;">

        <tr>
            <td class="auto-style1">
                Enter customer name
            </td>
            <td>
                <asp:TextBox ID="txtName" runat="server" 
                 Width="250px" MaxLength="30"></asp:TextBox>
            </td>
        </tr>

        <tr>
            <td>
                Select food type</td>
            <td>
                <table style="width:250px;">
                    <tr>
                        <td>
                            <asp:CheckBox ID="chkVeg" 
                             runat="server" Text="Veg"/>
                        </td>
                        <td>
                            <asp:CheckBox ID="chkNonVeg" 
                            runat="server" Text="NonVeg" />
                        </td>
                        <td>
                            <asp:LinkButton ID="lnkbtnShow" 
                           runat="server" onclick="lnkbtnShow_Click">
                           Show Items</asp:LinkButton>
                        </td>
                    </tr>
                </table>
            </td>
        </tr>

   <tr>
            <td>
                Foods of Selected Type(s)
            </td>
            <td>
                <asp:ListBox ID="lstFoodTypes" 
                 runat="server" Width="250px"                                               Rows="6" SelectionMode="Multiple">
                 </asp:ListBox>
            </td>
        </tr>

        <tr>
            <td></td>
            <td>
                <table>
                    <tr>
                        <td>
                            <asp:Button ID="btnSubmit" runat="server"                                   Text="Submit" Width="125px"                                               OnClick="btnSubmit_Click" />
                        </td>
                        <td>
                            <asp:Button ID="btnClear" runat="server"                                  Text="Clear" Width="125px"                                                OnClick="btnClear_Click" />
                        </td>
                    </tr>
                </table>
            </td>
        </tr>
        <tr>
            <td colspan="2">
                <asp:Label ID="lblMsg" runat="server" 
                 Text="Hello User..."></asp:Label>
            </td>
        </tr>
    </table>
    </form>
</body>

Code Behind – CheckBoxList.aspx.cs

public partial class Checkbox : System.Web.UI.Page
{
    protected void lnkbtnShow_Click(object sender, EventArgs e)
    {
        lstFoodTypes.Items.Clear();

        if (chkVeg.Checked)
        {
            //lstFoodTypes.Items.Add("Idly");
            //lstFoodTypes.Items.Add("Dosa");
            //lstFoodTypes.Items.Add("Pongal");
            ShowFoodsOf("Veg");
        }
        if (chkNonVeg.Checked)
        {
            //lstFoodTypes.Items.Add("Briyani");
            //lstFoodTypes.Items.Add("Fish fry");
            //lstFoodTypes.Items.Add("Parotta with chicken");
            ShowFoodsOf("NonVeg");
       }
    }
    protected void ShowFoodsOf(String ftype)
    {
        SqlConnection con;
        con = new SqlConnection(ConfigurationManager
            .ConnectionStrings["MyDBConStr"].ConnectionString);
        con.Open();

        string qry = "Select FoodName from tabFoods where                                               FoodType=@foodtype";

        SqlCommand cmd = new SqlCommand(qry, con);
        cmd.Parameters.AddWithValue("@foodtype", ftype);

        SqlDataReader dr = cmd.ExecuteReader();

        while (dr.Read())
        {
            lstFoodTypes.Items.Add(dr.GetString(0));
        }

        dr.Close();
        cmd.Dispose();
        con.Close();
    }

    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        SqlConnection con;
        con = new SqlConnection(ConfigurationManager
           .ConnectionStrings["MyDBConStr"].ConnectionString);
        con.Open();

        int ItemIndex =0;
        int totalItems = lstFoodTypes.Items.Count;

        while (ItemIndex < totalItems)
        {
            if (lstFoodTypes.Items[ItemIndex].Selected)
            {
                string qry = "insert into tabCustomerFoods                                                values(@custName,@foodName)";

                SqlCommand cmd = new SqlCommand(qry, con);
                cmd.Parameters.AddWithValue("@custName", txtName.Text);
                cmd.Parameters.AddWithValue("@foodName",                                                      lstFoodTypes.Items[ItemIndex].Text);

                cmd.ExecuteNonQuery();
            }
            ItemIndex++;
        }
        lblMsg.Text = "Food Details Saved...";
    }

    protected void btnClear_Click(object sender, EventArgs e)
    {
        txtName.Text = "";
        chkVeg.Checked = false;
        chkNonVeg.Checked = false;
        lstFoodTypes.SelectedIndex = -1;
        lstFoodTypes.Items.Clear();
        lblMsg.Text = "Enter next customer's choice";
    }
}

2 comments:

  1. UnknownMarch 21, 2020 at 11:42 AM

    protected void ShowFoodsOf(String ftype)
    {
    SqlConnection con;
    con = new SqlConnection(ConfigurationManager
    .ConnectionStrings["MyDBConStr"].ConnectionString);//exception in this line
    con.Open();
    }

    System.NullReferenceException: 'Object reference not set to an instance of an object.'

    System.Configuration.ConnectionStringSettingsCollection.this[string].get returned null.

    ReplyDelete
  2. Syed Nawas AhamedMarch 26, 2020 at 3:44 PM

    First you have to create database in SQL Server and
    You have to add connection string information in web.config file
    then try these example

    ReplyDelete

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