ASP.NET

14-Jun-06 20:50

Hi all,

I am using paging in datagrid and implemented paging successfully.
In my application I have checkbox and Id field in datagrid,On button click I want to save Ids which having checkbox status checked.

I implement solution thats is working correctly if datagrid having single page.But if I checked checkboxes from different pages in datagrid only last page Ids get saved.

I mean In paging if i want to save entries of two pages i could not do that.

For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)

If chk.Checked = True Then
lbl = DirectCast(gridItem.FindControl("ID"), Label)
'''''Saving code here
end if
next

Suamal15-Jun-06 1:01

15-Jun-06 1:01

You can save the checkbox ids in a viewstate and get it later while submitting.Otherwise use datagrid without paging.

Nagraj Naik15-Jun-06 4:34

15-Jun-06 4:34

Hi,
my checkbox is not binding to ant datafield.I am using viewstate to maintain Ids whose checkbox are checked but when loop

For Each gridItem In DataGrid1.Items
next

executes that consider datagrid items count=Item present on current page and not total datagrid item present on all pages.

I give some code for understanding

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not Page.IsPostBack Then
Fillgrid()
End If
Maintain_View()
Retrieve_Viewstate()
End Sub

Private Function Maintain_View()
Dim recordArray(DataGrid1.Items.Count - 1) As String
Dim n As Integer
Dim gridItem As DataGridItem
For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)
If chk.Checked Then
recordArray(n) = lbl.Text
n += 1
End If
Next
ViewState("recordArray") = recordArray
End Function
Private Function Retrieve_Viewstate()
Dim recordArray(DataGrid1.Items.Count - 1) As String
Dim n As Integer
Dim gridItem As DataGridItem
For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)
recordArray = ViewState("recordArray")
For n = 0 To DataGrid1.Items.Count - 1
If recordArray(n) = lbl.Text Then
chk.Checked = True
End If
Next
Next
End Function

I hope you help me...

Suamal15-Jun-06 18:57

15-Jun-06 18:57

I think I am late to answer you.Have you solved this?

Otherwise

Don't maintain viewstate for each page.

in not postback, initialize the viewstate (i.e clear it)

1.you have checked something in first page (2 check boxes)
2.Now you are moving to other, at that time save the checkbox's ids in viewstate. (viewstate has 2 values).
3.you have checked something in second page (3 check boxes)
4.You are moving to the third page, get the array from already existing view state and append second page's checkbox ids. (Now viewstate has 2+3 values)
5.while submitting , get it from viewstate and clear it.

6.Incase if you come to previous page,check with viewstate and populate the check boxed accordingly, if there is any change, change the viewstate value.

Hope it will help you.

Nagraj Naik15-Jun-06 19:49

15-Jun-06 19:49

Hi,
As you suggest I tried to use viewstate.But broblem is that for...loop
( For Each gridItem In DataGrid1.Items) is taking item count equals to items present in current page and not total item s in datagrid.So I can not retrive my first page values which are stored in viewstate.
I am sending changed code.Please have look at it.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not Page.IsPostBack Then
fillgrid()
End If
Maintain_View()
Retrieve_Viewstate()
end sub

Private Function Maintain_View()
Dim recordArray(DataGrid1.Items.Count - 1) As String
Dim n As Integer
Dim gridItem As DataGridItem
For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)
If chk.Checked Then
recordArray(n) = lbl.Text
ViewState.Add(lbl.Text, lbl.Text)
n += 1
End If
Next

End Function
Private Function Retrieve_Viewstate()
Dim recordArray(DataGrid1.Items.Count - 1) As String
Dim n As Integer
Dim gridItem As DataGridItem
For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)
recordArray = ViewState("recordArray")
For n = 0 To DataGrid1.Items.Count - 1
If ViewState.Item(n) = lbl.Text Then
chk.Checked = True
End If

Next
Next
End Function

Suamal15-Jun-06 20:11

15-Jun-06 20:11

Like this you can implement it on vb.net .

I jave given a rough code to do

private void Page_Load(object sender, System.EventArgs e)
{
// Put user code to initialize the page here

if(!IsPostBack)
{
Fillgrid();
//Initialize view state
ViewState["ID"]=null;
}

}

private void Fillgrid()
{
//To fill the grid
}

private void Maintain_View()
{
ArrayList ar=new ArrayList();

//Get Array List from Viewstate
if(ViewState["ID"]!=null)
ar=(ArrayList)ViewState["ID"];

//Check for items in the datagrid and accoring to the checkbox value
//add it to arraylist

foreach (DataGridItem dt in dgItems.Items)
{
//If check box valuw is checked
{
ar.Add(checkId); //Add to arrayList
}

}

//Set it to viewstate

ViewState["ID"]=ar;
}

private void Retrieve_View()
{
ArrayList ar=new ArrayList();
//Get Array List from Viewstate
if(ViewState["ID"]!=null)
ar=(ArrayList)ViewState["ID"];

//Compare this with datagrid items and populate the checkboxes
}

private void dgItems_PageIndexChanged(object source, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)
{
//while in pagination
dgItems.CurrentPageIndex =e.NewPageIndex();
Maintain_View();
Retrieve_View();
Fillgrid();

}

Nagraj Naik15-Jun-06 21:38

15-Jun-06 21:38

Hi Suamal,
Sorry For trouble.
As you suggest I make changes in my code.
Viewstate maintain Selected id list,But Loop count(For Each gridItem In DataGrid1.Items) is for current page only that means if i select 2 entries out of 5 from first page then 2 entries saved in viewstate,next i move to next page and select 3 items from second page Retrieve_Viewstate1's code

For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)
If Arr.Contains(lbl.Text) Then
chk.Checked = True
End If
Next

execute for selected 3 items from current page only.

I mean For Each gridItem In DataGrid1.Items...next loop is consider for current page item count instead of total number of items in datagrid

Is it correct loop or you are saying to use datagridview.

I hope you keep continue to answer.

I am sending latest code as below.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not Page.IsPostBack Then
fillgrid()
ViewState("ID") = System.DBNull.Value
End If

End Sub

Private Function Retrieve_Viewstate1()
Dim Arr As New ArrayList()
Dim n As Integer
Dim gridItem As DataGridItem

If Not (ViewState("ID") Is System.DBNull.Value) Then
Arr = CType(ViewState("ID"), ArrayList)
End If

For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)
If Arr.Contains(lbl.Text) Then
chk.Checked = True
End If
Next

End Function

Private Function Maintain_View1()
Dim Arr As New ArrayList()
Dim gridItem As DataGridItem
If Not (ViewState("ID") Is System.DBNull.Value) Then
Arr = CType(ViewState("ID"), ArrayList)
End If
For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)
If chk.Checked Then
Arr.Add(lbl.Text)
End If
Next
ViewState("ID") = Arr
End Function

Sub Pageing_Routine(ByVal s As Object, ByVal e As DataGridPageChangedEventArgs)
DataGrid1.CurrentPageIndex = e.NewPageIndex
Maintain_View1()
Retrieve_Viewstate1()
Fillgrid()
End Sub

Suamal15-Jun-06 22:58

15-Jun-06 22:58

Loop count of datagrid displays only the current page item count.
But in view state we can store all.

I will explain you how?

#Fill grid method()
1.Populate the grid (say 100 rows with 1 to 100 as ids)
clear viewstate

2.in first page select 2 checkboxes

3.In paging (to 2nd page)
add 2 ids to viewstate.
now it has 1,2.

while retriving
check for 1,2 ids in grid it will not be there.

4.In second page u select 3
add 3 ids with existing viewstate
now it has 1,2,11,12,13
while retriving
check for 1,2,11,12,13 ids in grid it will not be there.

5.goto 3rd page ,without selecting any ids.
now viewstate has 1,2,11,12,13

6.Return to 2nd page
now while retriving
check for 1,2,11,12,13 ids in grid 11,12,13 ids will be there.
If you change anything, you have to alter the viewstate.

# in maintain view

Private Function Maintain_View1()
Dim Arr As New ArrayList()
Dim gridItem As DataGridItem
If Not (ViewState("ID") Is System.DBNull.Value) Then
Arr = CType(ViewState("ID"), ArrayList)
End If
For Each gridItem In DataGrid1.Items
Dim chk As CheckBox = DirectCast(gridItem.FindControl("Status"), CheckBox)
Dim lbl As Label = DirectCast(gridItem.FindControl("ID"), Label)

//If already exists then, remove it from the list
If Arr.Contains(lbl.Text) Then
Arr.Remove();
End If

If chk.Checked Then
Arr.Add(lbl.Text)
End If
Next
ViewState("ID") = Arr
End Function

#call retrive view after fill GRid method

Sub Pageing_Routine(ByVal s As Object, ByVal e As DataGridPageChangedEventArgs)
DataGrid1.CurrentPageIndex = e.NewPageIndex
Maintain_View1()
Fillgrid()
Retrieve_Viewstate1()
End Sub

Nagraj Naik15-Jun-06 23:22