Get values of Gridview TextBox on Button Click

Hi,

I have a ITEMTemplate TextBox in a Gridview. I want to save values of Texboxes on button click. I am using following code ::

Source code:

Text="Insert Into Table" />


cs file:

protected void Page_Load(object sender, EventArgs e)
{
GetDetails();
}
private void GetDetails()
{
da = new SqlDataAdapter("select column_name from testing.information_schema.columns where table_name = 'emp'", con);
da.Fill(ds);
GridView1.DataSource = ds;
GridView1.DataBind();

}
protected void Button1_Click(object sender, EventArgs e)
{
for (int i = 0; i < GridView1.Rows.Count - 1; i++)
{
TextBox box1 = (TextBox)GridView1.Rows[i].Cells[0].FindControl("TextBox1");
string s = box1.Text;
}
}

But it is not working . I am getting s="" . please help me.

Thanks in advance.

Pankaj Singh