Displaying Gridview on Index Change Event of Dropdownlist

This blog explains the view for Gridview data using Dropdown selection.

Database Design

Query

  1. create table tbl_student(Student_ID int identity(1,1),  
  2. StudentName varchar(80),RollNo int,Class varchar(50),  
  3. Section varchar(50))  

Design

table design view

Now I am creating a Webform to insert some data to the database.
 
Dropdownindex.aspx:

Dropdownindex

Dropdownindex.aspx.cs:
  1. protected void Button1_Click(object sender, EventArgs e)  
  2. {  
  3.     try  
  4.     {  
  5.         string str = "Data Source=.;Initial Catalog=Wordpress;Integrated Security=True";  
  6.         SqlConnection con = new SqlConnection(str);  
  7.         SqlCommand cmd = new SqlCommand("insert into tbl_student ([StudentName],[RollNo],[Class],[Section]) values (@StudentName,@RollNo,@Class,@Section)", con);  
  8.         con.Open();  
  9.         cmd.Parameters.AddWithValue("@StudentName", TextBox1.Text);  
  10.         cmd.Parameters.AddWithValue("@RollNo", TextBox2.Text);  
  11.         cmd.Parameters.AddWithValue("@Class", DropDownList1.Text);  
  12.         cmd.Parameters.AddWithValue("@Section", DropDownList2.Text);  
  13.         cmd.ExecuteNonQuery();  
  14.         Label5.Text = "Submitted Successfully";  
  15.         con.Close();  
  16.     }  
  17.     catch(Exception ex)  
  18.     {  
  19.         throw ex;  
  20.     }  
  21.          
  22. }  
Output:

Output

Now create a Webform for Displaying the GridView on the Index change event of dropdownlist.
 
DropdownGrid.aspx:

Code:

Here I am hardcoding the dropdown list items:
  1. <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">  
  2.       <asp:ListItem>--Select--</asp:ListItem>  
  3.       <asp:ListItem Value="UKG">UKG</asp:ListItem>  
  4.       <asp:ListItem Value="I ">I </asp:ListItem>  
  5.       <asp:ListItem Value="II ">II</asp:ListItem>  
  6.       <asp:ListItem Value="III ">III</asp:ListItem>  
  7.       <asp:ListItem Value="IV ">IV </asp:ListItem>  
  8.       <asp:ListItem Value="V ">V</asp:ListItem>  
  9.       <asp:ListItem Value="VI ">VI</asp:ListItem>  
  10.       <asp:ListItem Value="VII ">VII</asp:ListItem>  
  11.       <asp:ListItem Value="VIII ">VIII</asp:ListItem>  
  12.       <asp:ListItem Value="IX ">IX</asp:ListItem>  
  13.       <asp:ListItem Value="X ">X</asp:ListItem>  
  14.       <asp:ListItem Value="XI ">XI</asp:ListItem>  
  15.       <asp:ListItem Value="XII ">XII</asp:ListItem>  
  16. </asp:DropDownList>  
dropdown list

DropdownGrid.aspx.cs:

Here is the code for displaying the GridView on Index change event of dropdownlist:
  1. protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)  
  2. {  
  3.     string str = "Data Source=.;Initial Catalog=Wordpress;Integrated Security=True";  
  4.     SqlConnection con = new SqlConnection(str);  
  5.     con.Open();  
  6.     SqlCommand cmd1 = new SqlCommand("Select StudentName,RollNo,Section from tbl_student where Class ='" + DropDownList1.SelectedItem.Text + "'", con);  
  7.     SqlDataAdapter da1 = new SqlDataAdapter(cmd1);  
  8.     DataSet ds = new DataSet();  
  9.     da1.Fill(ds, "tbl_student");  
  10.     GridView1.DataMember = "tbl_student";  
  11.     GridView1.DataSource = ds;  
  12.     GridView1.DataBind();  
  13.     con.Close();  
  14. }  
Output:

show data