Reading data from a textbox in a gridview ro which was added dynamically

Question

I've read forums which put text boxes in the gridviews footer for the user to enter a new record into a db. The problem with this is that the user would have to scroll down to the end of the gridview to enter new data. If the gridview has a lot of rows this isn't very intuitive.
The following code is how I'm dynamically adding a row under the header of a gridview. The row has text boxes for the user to enter data along with a linkbutton the user will click to insert the data entered into the text boxes into a SQL db.
I'm pretty new to asp.net and I haven't been able to figure out how to read the data from the textboxes when the linkbutton is clicked.
protected void gvDRM_RowDataBound(object sender, GridViewRowEventArgs e)
{
try
{
//**** Gridview Header ****
if (e.Row.RowType == DataControlRowType.Header)
//**** Gridview Data ****
if (e.Row.RowType == DataControlRowType.DataRow)
{
DataRowView dv = (System.Data.DataRowView)e.Row.DataItem;
if (dv.Row["UserID"].ToString() == "0")
{
e.Row.Visible = false;
}

//Create Link Button Object Instance
LinkButton lnkDeleteButton = (LinkButton)e.Row.FindControl("lnkDeleteButton");
//Add Javascript to link button
lnkDeleteButton.Attributes.Add("onclick", "javascript:return confirm('Are you sure you want to delete this Record?')");

}
//**** Gridview Footer ****
if(e.Row.RowType == DataControlRowType.Footer)
{
//**** Insert Add New Record row under the Header ****
GridViewRow row = new GridViewRow(-1, -1, DataControlRowType.DataRow, DataControlRowState.Normal);
// Add the Columns
row.Cells.AddRange(CreateCells());
// get a reference to the table that holds this row
Table tbl = (e.Row.Parent as Table);
// Add the row under the header
tbl.Rows.AddAt(1, row);
}
}
catch (Exception)
{
}
}
private TableCell[] CreateCells()
{
TableCell[] cells = new TableCell[5];
//**** Add Linkbutton ****
TableCell cell0;
LinkButton lnkBtn;
cell0 = new TableCell();
cell0.ColumnSpan = 1;
cell0.BackColor = System.Drawing.Color.LightGray;
lnkBtn = new LinkButton();
lnkBtn.Text = "Add";
lnkBtn.CommandName = "Insert";
cell0.Controls.Add(lnkBtn);
cells[0] = cell0;
//******************************************
//**** New Date Textbox ****
TableCell cell1;
TextBox txt1;
cell1 = new TableCell();
cell1.ColumnSpan = 1;
cell1.BackColor = System.Drawing.Color.LightGray;
txt1 = new TextBox();
txt1.Text = string.Format("{0:d}", DateTime.Now.Date).ToString();
txt1.Width = 80;
txt1.ID = "txtAddDate";

//Calendar control
cell1.Controls.Add(txt1);
CalendarExtender cal = new CalendarExtender();
cal.TargetControlID = "txtAddDate";
cell1.Controls.Add(cal);
cells[1] = cell1;
//******************************************
//**** New DRM Textbox ****
TableCell cell2;
TextBox txt2;
cell2 = new TableCell();
cell2.ColumnSpan = 1;
cell2.BackColor = System.Drawing.Color.LightGray;
txt2 = new TextBox();
txt2.Text = "";
txt2.Width = 80;
txt2.ID = "txtAddDRM";
cell2.Controls.Add(txt2);
// Watermark
TextBoxWatermarkExtender wmAddDRM = new TextBoxWatermarkExtender();
wmAddDRM.ID = "wmAddDRM";
wmAddDRM.TargetControlID = "txtAddDRM";
wmAddDRM.WatermarkText = "Enter DRM #";
wmAddDRM.WatermarkCssClass = "watermark";
cell2.Controls.Add(wmAddDRM);

// Reg Exp Validator
RegularExpressionValidator revAddDRM = new RegularExpressionValidator();
revAddDRM.ControlToValidate = "txtAddDRM";
revAddDRM.ErrorMessage = "Numeric";
revAddDRM.ValidationExpression = "^[0-9]*$";
cell2.Controls.Add(revAddDRM);
cells[2] = cell2;
//******************************************
//**** New Hours Textbox ****
TableCell cell3;
TextBox txt3;
cell3 = new TableCell();
cell3.ColumnSpan = 1;
cell3.BackColor = System.Drawing.Color.LightGray;
txt3 = new TextBox();
txt3.Text = "";
txt3.Width = 80;
txt3.ID = "txtAddHour";
cell3.Controls.Add(txt3);
// Watermark
TextBoxWatermarkExtender wmAddHour = new TextBoxWatermarkExtender();
wmAddHour.ID = "wmAddHour";
wmAddHour.TargetControlID = "txtAddHour";
wmAddHour.WatermarkText = "Enter Hours";
wmAddHour.WatermarkCssClass = "watermark";
cell3.Controls.Add(wmAddHour);
// Reg Exp Validator
RegularExpressionValidator revAddHours = new RegularExpressionValidator();
revAddHours.ControlToValidate = "txtAddHour";
revAddHours.ErrorMessage = "Numeric";
revAddHours.ValidationExpression = "^[0-9]*\\.?[0-9]*$";
cell3.Controls.Add(revAddHours);
cells[3] = cell3;
//******************************************
//**** New Comments Textbox ****
TableCell cell4;
TextBox txt4;
cell4 = new TableCell();
cell4.ColumnSpan = 1;
cell4.BackColor = System.Drawing.Color.LightGray;
txt4 = new TextBox();
txt4.Text = "";
txt4.Width = 400;
txt4.ID = "txtAddComment";
cell4.Controls.Add(txt4);
// Watermark
TextBoxWatermarkExtender wmAddComments = new TextBoxWatermarkExtender();
wmAddComments.ID = "wmAddComments";
wmAddComments.TargetControlID = "txtAddComment";
wmAddComments.WatermarkText = "Enter Comments (optional)";
wmAddComments.WatermarkCssClass = "watermark";
cell4.Controls.Add(wmAddComments);
cells[4] = cell4;
//******************************************
return cells;
}