Unable to update the textbox values in the gridview[C# ASP.NET]

See more:

C#

ASP.NET

while saving and binding data to gridview the code is fine.but while updating the datatable is filled with while i binded.no updation values are getting to datatable
my code as below

What I have tried:

int rowIndex = 0;

if (ViewState["CurrentTable"] != null)
{

DataTable dt = (DataTable)ViewState["CurrentTable"];

if (dt.Rows.Count <=5)
{

for (int i = 0; i < dt.Rows.Count; i++)
{

DropDownList box1 = (DropDownList)GridView1.Rows[rowIndex].Cells[1].FindControl("DropDownList1");
TextBox box2 = (TextBox)GridView1.Rows[rowIndex].Cells[2].FindControl("TextBox2");
TextBox box3 = (TextBox)GridView1.Rows[rowIndex].Cells[3].FindControl("TextBox3");
TextBox box4 = (TextBox)GridView1.Rows[rowIndex].Cells[4].FindControl("TextBox4");
TextBox box5 = (TextBox)GridView1.Rows[rowIndex].Cells[5].FindControl("TextBox5");
TextBox box6 = (TextBox)GridView1.Rows[rowIndex].Cells[6].FindControl("TextBox6");
box1.Text = dt.Rows[i]["UNITS"].ToString();

box2.Text = dt.Rows[i]["CONVERSION"].ToString();

box3.Text = dt.Rows[i]["BARCODE"].ToString();

box4.Text = dt.Rows[i]["RATE 1"].ToString();

box5.Text = dt.Rows[i]["RATE 2"].ToString();

box6.Text = dt.Rows[i]["PRINT TEXT"].ToString();
rowIndex++;

}

}

}