<VS03>How to make the textbox text remain after postback

**nUflAvOrS** · Feb 10th, 2009, 04:11 AM

Hi All,

I design a datagrid which enabled user to edit,delete and add new record inside the grid.

The add button and textbox control embeded in datagrid footer section.

I want to do a validation when user trying to insert new record into database.

What I want to do is check if templatecolumn textbox is blank then pop up a messagebox and

setfocus to textbox until this stage all is fine but when everything completed the page will postback and

reload the text inside textbox and cleared.

I don't want the text inside the textbox clear after BLANK found. It will remain inside the textbox with

unchanged.

Hereon, I posted my html code and code behind.

HTML Code:

<body ms_positioning="GridLayout" id="myBody" runat="server">

ASP Code:

Private Sub dgSchoolName_ItemCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles dgSchoolName.ItemCommand
        Dim pStrSql As String, myds As New DataSet, mydt As DataTable
        Dim Txtbox As TextBox = DirectCast(e.Item.Cells(1).FindControl("txtSchoolNo"), TextBox)
        Dim Txtbox_1 As TextBox = DirectCast(e.Item.Cells(2).FindControl("txtSchoolNameA"), TextBox)
        Dim FTextbox As String = Txtbox.Text
        Dim FTextbox_1 As String = Txtbox_1.Text
        Dim myBody As System.Web.UI.HtmlControls.HtmlGenericControl = CType(Page.FindControl("myBody"), System.Web.UI.HtmlControls.HtmlGenericControl)
 
        If FTextbox = vbNullString Then
            General_F.Setfocus(Txtbox, Page, "Form1")
 
            MsgBox1.alert("School No Cannot Be Blank")
 
            Exit Sub
        ElseIf FTextbox_1 = vbNullString Then
            General_F.Setfocus(Txtbox_1, Page, "Form1")
            MsgBox1.alert("School Name Cannot Be Blank")
 
            myBody.Attributes.Add("onload", "document.getElementById('txtSchoolNo').value = '" & FTextbox & "'")
 
        Exit Sub
        End If
End Sub

I have been posted my code above. I hope someone can help me thanks :-)

**mendhak** · Feb 10th, 2009, 10:17 AM

If I'm understanding you right, you're dynamically, on the fly creating a new textbox in a new row in the datagrid and attempting to save that info and on postback, the values are disappearing. Yes? No?

If you dynamically created some controls in the grid, you'll need to recreate those controls in an event such as Page_Init. This way, the viewstate can be re-applied to those controls and the values preserved.

**nUflAvOrS** · Feb 10th, 2009, 10:35 PM

Originally Posted by mendhak

If I'm understanding you right, you're dynamically, on the fly creating a new textbox in a new row in the datagrid and attempting to save that info and on postback, the values are disappearing. Yes? No?

If you dynamically created some controls in the grid, you'll need to recreate those controls in an event such as Page_Init. This way, the viewstate can be re-applied to those controls and the values preserved.

Thanks guru mendhak I have been solved the problem.

I posted my code here.

asp Code:

Private Sub dgSchoolName_ItemDataBound1(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles dgSchoolName.ItemDataBound
 
If e.Item.ItemType = ListItemType.Footer Then
            Dim txtSchoolNo As TextBox = CType(e.Item.Cells(1).FindControl("txtSchoolNo"), TextBox)
            Dim txtSchoolName As TextBox = CType(e.Item.Cells(2).FindControl("txtSchoolNameA"), TextBox)
            If Not txtSchoolNo Is Nothing And Not viewstate("SchoolNo") = vbNullString Then
                txtSchoolNo.Text = viewstate("SchoolNo")
            End If
            If Not txtSchoolName Is Nothing And Not viewstate("SchoolName") = vbNullString Then
                txtSchoolName.Text = viewstate("SchoolName")
            End If
end sub
 
Private Sub Page_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.PreRender
 
        Dim intFooter As Integer = dgSchoolName.Controls(0).Controls.Count - 2
        Dim txtSchoolNo As TextBox = CType(dgSchoolName.Controls(0).Controls(intFooter).FindControl("txtSchoolNo"), TextBox)
        Dim txtSchoolName As TextBox = CType(dgSchoolName.Controls(0).Controls(intFooter).FindControl("txtSchoolNameA"), TextBox)
        If Page.IsPostBack Then
            ViewState("SchoolNo") = txtSchoolNo.Text
            ViewState("SchoolName") = txtSchoolName.Text
        End If
    End Sub

I still have some question to ask you.

Is it the best way ?

I need to remove all viewstate ?

Thanks a billion

**nUflAvOrS** · Feb 10th, 2009, 11:14 PM

Sorry Guru another problem occured.

I will get an error if I want to display another page of datagrid.

Code:

Specified argument was out of the range of valid values. Parameter name: index 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. Parameter name: index

Source Error: 


Line 325:        Dim myds As New DataSet
Line 326:        Dim mydt As DataTable
Line 327:        Dim Txtbox As TextBox = DirectCast(e.Item.Cells(1).FindControl("txtSchoolNo"), TextBox)
Line 328:        Dim Txtbox_1 As TextBox = DirectCast(e.Item.Cells(2).FindControl("txtSchoolNameA"), TextBox)
Line 329:        Dim FTextbox As String = Txtbox.Text

Above is my error message
error highlighted on line 327

**mendhak** · Feb 11th, 2009, 02:00 PM

Yes, your way is fine.

You're getting an error. What method is this happening in?

**nUflAvOrS** · Feb 12th, 2009, 01:26 AM

After I try to open another page in datagrid. (Custom paging).

By using quickwatch I could not get the textbox value.

**mendhak** · Feb 13th, 2009, 05:55 AM

Do a quickwatch on

e.Item.Cells(1).FindControl("txtSchoolNo")

To see if it evaluates to null.

Also show your code.

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