Gridview PageIndex not changing on page_Load event - c#

I'm trying to change pageindex on page_Load event but its not working.
I can change page by clicking links in the page after page loaded.
If this info necessary GridView in UpdatePanel.
protected void Page_Load(object sender, EventArgs e)
{
/*...Some Codes...*/
//I'm trying to change page like this.
GridView1.PageIndex = Index;
GridViewPageEventArgs ea = new GridViewPageEventArgs(GridView1.PageIndex);
GridView1_PageIndexChanging(sender, ea);
}
protected void GridView1_PageIndexChanging(object sender,GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
}

I believe that you need to rebind the data to your gridview after you change the page index.

Related

Data not loading on pageload with postback

I am having a problem. Data is not loading once the page loads. I have to choose an item on the dropdown list for it to load. I need it to load even before I choose any item on the drop down list.
This is my code behind.
protected void ddlPeriodStamp_SelectedIndexChanged(object sender, System.EventArgs e)
{
string selectedGroup = string.Empty;
DropDownList ddlItemGroup = (DropDownList)sender;
if (ddlItemGroup.SelectedValue != null)
TreatmentGroup = ddlItemGroup.SelectedValue;
ApplyGridFilter(ddlItemGroup.SelectedValue);
}
protected void ApplyGridFilter(string TreatmentGroup)
{
string selectedGroup = string.Empty;
DBDataSource1.State.BusinessObject.DataPump.FormFilters.Clear();
DBDataSource1.State.BusinessObject.DataPump.FormFilters.Add("TreatmentGroup", TreatmentGroup);
DBDataSource1.State.BusinessObject.Fill(null);
MedicalSchemeDetailGrid.DataBind();
}
protected void Page_LoadComplete(object sender, System.EventArgs e)
{
if (!this.IsPostBack)
ApplyGridFilter(string.Empty);
}
Call ApplyGridFilter(string.Empty); while ispostBack is false and call ApplyGridFilter(ddlItemGroup.SelectedValue); while ispostBack is true
protected void Page_LoadComplete(object sender, System.EventArgs e)
{
if (this.IsPostBack)
{
ApplyGridFilter(ddlItemGroup.SelectedValue);// it will hit on first time page load
}
else
{
ApplyGridFilter(string.Empty);// it will hit while you change the dropdown items, But you should set true for **IsAutoPostBack** property on dropsownlist.
}
}
You need to fill your data in Page_Load event not in Page_LoadComplete event. According to MSDN:
The LoadComplete event occurs after all postback data and view-state
data is loaded into the page and after the OnLoad method has been
called for all controls on the page.
protected void Page_Load(object sender, System.EventArgs e)
{
if (!this.IsPostBack)
ApplyGridFilter(string.Empty);
}

Paging not working in Datagrid?

I am searching for some data from a database into a datagrid. When I applied paging on it, on clicking the next link of paging the datagrid vanishes without showing anything. I used datagrid.databind() in pageload too when it's postback or I even made a postback event method named datagridname_onpageindexchanged() as :
protected void DataGridSearchResults_PageIndexChanged(object source, DataGridPageChangedEventArgs e)
{
DataGridSearchResults.currentpageindex=e.newpageindex;
DataGridSearchResults.databind();
}
Your aspx should include Paging :-
<asp:DataGrid ID="DataGridSearchResults" runat="server" AllowPaging="true" PageSize="10"
OnPageIndexChanged="DataGridSearchResults_PageIndexChanged">
If grid is having data at pageload, it should bind like this :-
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
//Bind your grid here.
}
}
Then the page index changed function :-
protected void DataGridSearchResults_PageIndexChanged(object source, DataGridPageChangedEventArgs e)
{
DataGridSearchResults.CurrentPageIndex = e.NewPageIndex;
//Bind your Grid here again.
}
If(! IsPostBack)
{
// Bind your dataGrid
}
see this link http://msdn.microsoft.com/enus/library/system.web.ui.webcontrols.datagrid.allowcustompaging.aspx
You need to set DataSource here for your datagrid.
protected void DataGridSearchResults_PageIndexChanged(object source, DataGridPageChangedEventArgs e)
{
DataGridSearchResults.CurrentPageIndex = e.NewPageIndex;
DataGridSearchResults.DataSource = YourDataSource;
DataGridSearchResults.DataBind();
}
Also ,If you are binding your grid in Page_Load, Make sure you are not binding your grid outside of if(!IsPostBack){}. Otherwise you will loose data on each postback.
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
//Bind Your Grid Here
}
}

Pagination of GridView in ASP.NET (Won't go to page 2,3, etc.)

I have a Gridview and I want to set Pagination. So far I have:
<asp:GridView ID="grdActivity"
runat="server"
AutoGenerateColumns="False"
AllowPaging="True"
PageSize="30"
OnPageIndexChanging="gridView_PageIndexChanging">
C# code on the back is:
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
dsActivity myDataSet = new dsActivity();
myDataSet = clsDataLayer.GetActivity(Server.MapPath("DB.mdb"));
grdActivity.DataSource = myDataSet.Tables["tblActivity"];
grActivity.DataBind();
}
}
protected void gridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
grdActivity.PageIndex = e.NewPageIndex;
grdActivity.DataBind();
}
I get no errors but when I press any other page (2 and on), nothing shows, just a blank page and the GridView disappears. Am I missing something? I see hundreds of pages showing this exact code to do this.
You will need to re-assign your datasource property. After the postback the grActivity.DataSource is null, and calling DataBind on it will clear the grid.
protected void gridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
//re-assign your DataSource
dsActivity myDataSet = new dsActivity();
myDataSet = clsDataLayer.GetActivity(Server.MapPath("DB.mdb"));
grdActivity.DataSource = myDataSet.Tables["tblActivity"];
//Set the new page index
grdActivity.PageIndex = e.NewPageIndex;
//apply your changes
grdActivity.DataBind();
}
Some notes:
you should consider re-factoring the code that brings you the data into a single method called on Page_Load and inside the gridview_PageIndexChanging (see #ekad's answer)
if you have a lot of data you should consider paging the data directly on the database. Right now if your table has 500 rows all will be loaded into the dataset even if just a small part of it (the page size) will be displayed in the grid
Hi you please keep the code in a separate method and call it in page load event and page index changed event, something like
protected void FillGrid()
{
dsActivity myDataSet = new dsActivity();
myDataSet = clsDataLayer.GetActivity(Server.MapPath("DB.mdb"));
grdActivity.DataSource = myDataSet.Tables["tblActivity"];
grActivity.DataBind();
}
and in the page index changing event
protected void gridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
grdActivity.PageIndex = e.NewPageIndex;
FillGrid();
}
and in page load in !post back event simply call the method, like
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
FillGrid();
}
}
You have to set the data source of grdActivity before calling grdActivity.DataBind() in gridView_PageIndexChanging method. I would also suggest creating a separate method to avoid repeating the same code in Page_Load and gridView_PageIndexChanging
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
grdActivity.DataSource = GetDataSource();
grdActivity.DataBind();
}
}
private DataTable GetDataSource()
{
dsActivity myDataSet = new dsActivity();
myDataSet = clsDataLayer.GetActivity(Server.MapPath("DB.mdb"));
return myDataSet.Tables["tblActivity"];
}
protected void gridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
grdActivity.PageIndex = e.NewPageIndex;
grdActivity.DataSource = GetDataSource();
grdActivity.DataBind();
}

Databinding action cancels selectedindexchanging event

I'm using ListView server control to represent some data. When I fire a Select command, Page does postback properly; but if i bind data source in pageload, selectedindexchanging event is being cancelled. I toggled databinding to comment in pageload and it worked properly.
Here is my databinding method.
public void BindData()
{
lstSamples.DataSource = (Session["AnalyzeApp"] as AnalizBasvurusu).SampleInfos;
lstSamples.DataKeyNames = new string[] {"Key"};
lstSamples.DataBind();
}
And i call it that way
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostback)
BindData();
}
Thanks in advance.
Call BindData() after you handle your events(SelectedIndexChanging..etc):
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostback)
BindData();
}

error paging and editing in gridview

I had gridview which retrieve Products from database by sqldatasource1 ,and my manager asked me to filter this gridview by DDL to filter gridview with specfic Model ,I add some function on gridview as edit,paging .I did my code well and gridview filtred by the Model_Id which come from DDL .But when I tried to edit any product or navigate through paging I faced this error (The GridView 'GridView1' fired event PageIndexChanging which wasn't handled. )when paging ,And this for editing (The GridView 'GridView1' fired event RowEditing which wasn't handled.)
So please any one help me.
(CS)
protected void Page_Load(object sender, EventArgs e)
{
BindGridFunction();
}
private void BindGridFunction()
{
if (DDLModel.SelectedIndex < 0)
{
GridView1.DataSource = SDSModel;
GridView1.DataBind();
}
else
{
GridView1.DataSource = SDSModel2;
GridView1.DataBind();
}
}
You need to explicitly handle PageIndexChanging() and RowEditing() event through code behind.
like
protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
GridView1.DataBind();
}
public void GridView1_RowEditing(Object sender, GridViewEditEventArgs e)
{
//do your code here
}

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