Update button Condition

Question

private void btnUpdate_Click(object sender, EventArgs e)

{

Entity ent = new Entity();

BAL b = new BAL();

ent.intId = (int)gvData.SelectedRows[0].Cells["Id"].Value;

if (ent.intId != 0)

{

ent.strEmail = txtEmail.Text;

ent.strName = txtName.Text;

ent.strSalary = txtSalary.Text;

DL dl = new DL();

dl.Update(ent);

DataTable dt = dl.Display(ent);

gvData.DataSource = dt;

}

b.Clear(ent);

txtEmail.Text = txtName.Text = txtSalary.Text = " ";

}

 

 

 

Hello,

This is my Code for update. Now i want to put condition for update. Like if I put new record and by mistake I click Update then I got ("Index was out of range. Must be non-negative and less than the size of the collection.") Error. So I want to remove it. 

If you have any idea then Please Suggest.

Thanks in advance