Solved it.
private void SetPreviousData()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dt = (DataTable)ViewState["CurrentTable"];
if (dt.Rows.Count > 0)
{
for (int i = 0; i < dt.Rows.Count; i++)
{
TextBox TextBoxName = (TextBox)grvStudentDetails.Rows[rowIndex].Cells[1].FindControl("txtName");
TextBox TextBoxAge = (TextBox)grvStudentDetails.Rows[rowIndex].Cells[2].FindControl("txtAge");
TextBox TextBoxAddress =
(TextBox)grvStudentDetails.Rows[rowIndex].Cells[3].FindControl("txtAddress");
RadioButtonList RBLGender =
(RadioButtonList)grvStudentDetails.Rows[rowIndex].Cells[4].FindControl("RBLGender");
DropDownList DrpQualification =
(DropDownList)grvStudentDetails.Rows[rowIndex].Cells[5].FindControl("drpQualification");
//Added these lines
Classes.CRUD obj = new Classes.CRUD();
DrpQualification.DataSource = obj.ShowAllAccounts();
DrpQualification.DataBind();
//****************
TextBoxName.Text = dt.Rows[i]["Col1"].ToString();
TextBoxAge.Text = dt.Rows[i]["Col2"].ToString();
TextBoxAddress.Text = dt.Rows[i]["Col3"].ToString();
RBLGender.SelectedValue = dt.Rows[i]["Col4"].ToString();
DrpQualification.SelectedValue = dt.Rows[i]["Col5"].ToString();
rowIndex++;
}
}
}
}