Question

I am populating the GridView with following code on basis of Numeric data put in the textbox and clicking the button.
But it is giving the following error.
Error converting data type varchar to float.
As my database column ‘matri_perct’ has datatype ‘float’.

protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {
            con = new SqlConnection(ConfigurationManager.ConnectionStrings["SQL Connection String"].ConnectionString);con.Open();
        com = new SqlCommand("SELECT * FROM stdtable WHERE matri_perct >  @Percent", con);
        com.Parameters.AddWithValue("Percent", float.Parse(txtPercent.Text));
        com.ExecuteNonQuery();
            SqlDataAdapter dataadapter = new SqlDataAdapter();
            DataSet ds = new DataSet();
            dataadapter.Fill(ds, "Data");
            GridView1.DataSource = ds;
            GridView1.DataMember = "Data";
            con.Close();
        }
        catch (System.Exception err)
        {
            Label1.Text = err.Message.ToString();
        }
    }

My GridView .aspx code is declared as

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" AutoGenerateColumns="False" DataKeyNames="univ_regno" DataSourceID="" EnableModelValidation="True">
    <Columns>
        <asp:BoundField DataField="school" HeaderText="School" 
            SortExpression="school" />
        <asp:BoundField DataField="univ_regno" HeaderText="Univ R.No." ReadOnly="True" 
            SortExpression="univ_regno" />
        <asp:BoundField DataField="colge_rollno" HeaderText="Coll. R.No." 
            SortExpression="colge_rollno" />
        <asp:BoundField DataField="branch" HeaderText="Branch" 
            SortExpression="branch" />
        <asp:BoundField DataField="sem" HeaderText="Sem" SortExpression="sem" />
        <asp:BoundField DataField="name" HeaderText="Name" SortExpression="name" />
        <asp:BoundField DataField="f_name" HeaderText="F.Name" 
            SortExpression="f_name" />
        <asp:BoundField DataField="date_birth" HeaderText="DOB" 
            SortExpression="date_birth" />

        <asp:BoundField DataField="mob" HeaderText="Mobile" 
            SortExpression="mob" />
        <asp:BoundField DataField="email" HeaderText="E-mail" SortExpression="email" />
        <asp:BoundField DataField="matri_perct" HeaderText="Matric %" 
            SortExpression="matri_perct" />
        <asp:BoundField DataField="intermed_perct" HeaderText="Intermediate %" 
            SortExpression="intermed_perct" />
        <asp:BoundField DataField="grad_perct" HeaderText="UG %" 
            SortExpression="grad_perct" />
        <asp:BoundField DataField="post_grad_perct" HeaderText="PG %" 
            SortExpression="post_grad_perct" />
        <asp:BoundField DataField="other_perct" HeaderText="Other %" 
            SortExpression="other_perct" />
        <asp:BoundField DataField="no_backlogs" HeaderText="Backlogs" 
            SortExpression="no_backlogs" />
        <asp:BoundField DataField="Password" HeaderText="Password" 
            SortExpression="Password" />
    </Columns>
</asp:GridView>
  <asp:SqlDataSource ID="studentprofile" runat="server" 
        ConnectionString="<%$ ConnectionStrings:SQL Connection String %>" 

        SelectCommand="SELECT DISTINCT [school], [univ_regno], [colge_rollno], [branch], [sem], [name], [f_name], [date_birth], [cores_add], [mob], [email], [matri_perct], [intermed_perct], [grad_perct], [post_grad_perct], [other_perct], [no_backlogs], [Password] FROM [stdtable] ORDER BY [branch], [univ_regno]">
    </asp:SqlDataSource>

Answer 1

I have solved my question with the help of @Bob Kaufman & @rene
The complete solution of my question is following:

protected void Button1_Click(object sender, EventArgs e)
{
    try
    {

        con = new SqlConnection(ConfigurationManager.ConnectionStrings["SQL Connection String"].ConnectionString);
        con.Open();
        com = new SqlCommand("SELECT * FROM stdtable WHERE matri_perct >  @Percent", con);
        com.Parameters.AddWithValue("@Percent", float.Parse(txtPercent.Text));
        SqlDataReader reader = com.ExecuteReader();  // execute SELECT statement, store result in data reader
        GridView1.DataSource = reader;
        GridView1.DataBind();
        con.Close();
         }
    catch (System.Exception err)
    {
        Label1.Text = err.Message.ToString();
    }
}

And then i have changed the AllowPaging=false

It works 😉