I have a usercontrol.Inside usercontrol I have a datalist and sqldatasource.Sqldatasource needs a parameter to databind the datalist.Usercontrol gets a parameter by this way,
private string _urunIDparam;
public string urunIDparam
{
get { return _urunIDparam; }
set {_urunIDparam = value; }
}
And then this parameter is added to the sqldatasource in onprerender of usercontrol by this way,
protected override void OnPreRender(EventArgs e)
{
SqlDataSourceHareketler.SelectParameters["urunID"].DefaultValue = urunIDparam;
DataListHareketAna.DataBind();
base.OnPreRender(e);
}
And the usercontrols parameter is given from a button that is placed aspx page like this,
protected void Button1_Click(object sender, EventArgs e)
{
MyUserControl1.urunIDPARAM = urunID;
}
And button and usercontrol is placed in an updatepanel inside an aspx page like this,
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<uc2:MyUserControl ID="MyUserControl1" runat="server" />
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click"/>
</ContentTemplate>
</asp:UpdatePanel>
And the problem when I hit a button inside datalist, my usercontrol disappears (datalist loses its items).
It sounds like you may need to do a postback check around your functions within the controls. I have seen this exact issue before, and I think this is what I had to do, but it has been awhile.
if (!IsPostback) {
//LoadData
}
Related
I have a LinkButton in aspx page.
<asp:TextBox ID="textBoxNote" runat="server" />
<asp:LinkButton ID="linkButtonUpdateNote" Text="Update" OnClick="ButtonUpdateNoteClicked" runat="server" />
the click event handler has the following code
protected void ButtonUpdateNoteClicked(object sender, EventArgs e)
{
var note = textBoxNote.Text;
}
On Postback textBoxNote.Text is empty. I don't get the posted value. How to get the value?
It seems like you are possibly resetting the value in your Page_Load.
Check that you are using IsPostback check in the Page_Load function. see - http://msdn.microsoft.com/en-us/library/system.web.ui.page.ispostback.aspx
private void Page_Load()
{
if (!IsPostBack)
{
DoThisOnce();
}
DoThisOnEachPostback();
}
I have a repeater which includes a radio button in each item, and the whole thing sites inside an update panel. When I select a radio button the whole page reloads. Why is it not just updating the update panel. I've reduced this to a pretty simple example to avoid clutter. Code here...
ASPX...
<asp:ScriptManager ID="SM1" runat="server" />
<asp:UpdatePanel ID="up1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Repeater runat="server" ID="history">
<ItemTemplate>
<asp:RadioButton runat="server" ID="radioButton" AutoPostBack="true" GroupName="HistoryGroup" OnCheckedChanged="RadioButton_CheckChanged" /><br />
</ItemTemplate>
</asp:Repeater>
<p><asp:Literal runat="server" ID="output" /></p>
</ContentTemplate>
</asp:UpdatePanel>
Code...
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
List<int> list = new List<int>();
for (int i = 0; i < 20; i++)
list.Add(i);
history.DataSource = list.ToArray();
history.DataBind();
}
}
protected void RadioButton_CheckChanged(Object sender, EventArgs e)
{
output.Text = DateTime.Now.ToString();
}
}
Setting ClientIDMode=Auto on the RadioButton should fix it (it's an infamous .NET bug, http://connect.microsoft.com/VisualStudio/feedback/details/584991/clientidmode-static-in-updatepanel-fails-to-do-async-postback)
please add up1.Update() after output.Text = DateTime.Now.ToString(). Your RadioButton is not the trigger for updatepanel
Turns out the solution was to remove the GroupName from the RadioButton. When I remove this tag it fires asynchronously and just updates the panel. I don't actually need this tag anyway (due to the known bug where GroupName doesn't work on RadioButtons in Repeaters) as I handle the grouping within my click event (i.e. uncheck any other RadioButtons of the same name in other repeater items).
I want load two user controls on demand.
asp:UpdatePanel ID="UpdatePanel1" runat="server"
ContentTemplate
asp:Button ID="Button1" runat="server" Text="Button" UseSubmitBehavior="false"
OnClick="Button1_Click" /
div id='Div_UserControlPlace' enableviewstate="true" runat="server"
/div
/ContentTemplate
Triggers
asp:PostBackTrigger ControlID="Button1" /
/Triggers
/asp:UpdatePanel
asp:UpdatePanel ID="UpdatePanel2" runat="server"
ContentTemplate
asp:Button ID="Button2" runat="server" Text="Button" UseSubmitBehavior="false"
OnClick="Button2_Click" /
div id='Div_UserControlPlace2' enableviewstate="true" runat="server"
/div
/ContentTemplate
aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
Control FeaturedProductUserControl = new Control();
FeaturedProductUserControl = LoadControl("WebUserControl1.ascx");
FeaturedProductUserControl.EnableViewState = true;
Div_UserControlPlace.Controls.Add(FeaturedProductUserControl);
}
protected void Button2_Click(object sender, EventArgs e)
{
Control FeaturedProductUserControl2 = new Control();
FeaturedProductUserControl2 = LoadControl("WebUserControl2.ascx");
FeaturedProductUserControl2.EnableViewState = true;
Div_UserControlPlace2.Controls.Add(FeaturedProductUserControl2);
}
I load the first user control by clicking on the first button - this works properly but when I click on the other button to load the second UserControl, the first UserControl disappears and the second UserControl loads.
Thanks
IFA_User
You should use the Placeholder control to dynamically add your controls to the form.
Take a look at my last responses about dynamic controls:
OnClick event of dynamically created LinkButtons is not working
Dynamically Added DropDownlists Are Not Firing SelectedIndexChanged Event
Dynamically create an ImageButton
Now I already have some code working for demo purpose, each dynamic user controls keeps its state across post backs
This is the output:
ASPX
<asp:PlaceHolder runat="server" ID="addresses" /><br />
<asp:Button Text="Add Address" runat="server" ID="addAddress" OnClick="addAddress_Click" />
ASPX Code behind
protected void Page_PreLoad(object sender, EventArgs e)
{
for (int i = 0; i < this.DynamicControlsCount; i++)
{
var c = this.LoadControl("~/AddressControl.ascx");
this.addresses.Controls.Add(c);
}
}
protected void addAddress_Click(object sender, EventArgs e)
{
this.DynamicControlsCount++;
var c = this.LoadControl("~/AddressControl.ascx");
this.addresses.Controls.Add(c);
}
protected int DynamicControlsCount
{
get
{
if (this.ViewState["ac"] == null)
{
return 0;
}
return (int)this.ViewState["ac"];
}
set
{
this.ViewState["ac"] = value;
}
}
ASCX
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="AddressControl.ascx.cs" Inherits="WebApplication1.AddressControl" %>
<asp:Panel ID="Panel1" runat="server" GroupingText="Address" DefaultButton="btnSave">
Street: <asp:TextBox runat="server" ID="txtStreet" /><br />
City: <asp:TextBox runat="server" ID="txtCity" /><br />
<asp:Button Text="Save" runat="server" ID="btnSave" OnClick="btnSave_Click" />
</asp:Panel>
<asp:Panel runat="server" GroupingText="Address Summary" Visible="false" ID="summary">
<asp:Label ID="lblStreet" runat="server" /><br />
<asp:Label ID="lblCity" runat="server" />
</asp:Panel>
ASCX Code behind
protected void btnSave_Click(object sender, EventArgs e)
{
this.summary.Visible = true;
this.lblCity.Text = "Selected city: " + this.txtCity.Text;
this.lblStreet.Text = "Selected street: " + this.txtStreet.Text;
}
When a user control is created in the HTML, asp.net will persist across postbacks without any user interaction. But if you are loading them programatically (dynamically), they will not persist accross postbacks. So if you load them programmatically, you have the added task of persisting them programmatically as well. Use the ViewState (or Session I suppose) to store what has been loaded and perhaps any other necessary information that needs to be loaded between postbacks. Every single postback will require you to reload every control or else they will disappear.
There are couple of ways of doing it:
U can load the UserControls using Ajax. Benefit of using Ajax, is ur page does not get post back, thus for example, on click event of Button1, call a ajax(traditional/Jquery) to load UserControl1, and on button click of Button2 User control2.
Put the two button in two different updated panel, by doing this the click event will only refresh a part of ur page.
U have to save somewhere (ViewState/Session),which buttons are clicked, and upon clicking of any button check the value of that variable, and explicit load the control.
Points to note - If u want to get ur data back when ur page made a complete postback, then u have to add the controls keeping in mind the Page load event cycle.
Note: This question has been completely modified now that I have a simpler example.
I have set up a sample page which only has a ListView and ObjectDataSource. The first time the page comes up (!IsPostBack), my GetList method is called once. After paging (IsPostBack), the GetList method is called twice--the first time with the old paging values and the second time with the new values.
If I set EnableViewState="true" on the ListView, then the GetList method is only called once. It seems to me that the ListView wants an "initial state", which it either gets from ViewState or by re-running the method.
Is there any way to disable ViewState on the ListView and also prevent SelectMethod from being called twice?
ASPX page:
<asp:ListView ID="TestListView" runat="server" DataSourceID="ODS" EnableViewState="false">
<LayoutTemplate>
<asp:PlaceHolder ID="itemPlaceHolder" runat="server" />
<asp:DataPager ID="TestPager" runat="server" PageSize="10">
<Fields>
<asp:NumericPagerField />
</Fields>
</asp:DataPager>
</LayoutTemplate>
<ItemTemplate>
<div><%# Eval("Title") %></div>
</ItemTemplate>
</asp:ListView>
<asp:ObjectDataSource ID="ODS" runat="server" SelectMethod="GetList" SelectCountMethod="GetListCount"
TypeName="Website.Test" EnablePaging="true" />
ASPX code-behind:
namespace Website
{
public partial class Test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
public IList<DataItem> GetList(int maximumRows, int startRowIndex)
{
return GetListEnumerable().Skip(startRowIndex).Take(maximumRows).ToList();
}
public IEnumerable<DataItem> GetListEnumerable()
{
for (int i = 0; i < 100; i++)
{
yield return new DataItem { Title = i.ToString() };
}
}
public int GetListCount()
{
return 100;
}
}
public class DataItem
{
public string Title { get; set; }
}
}
Either turn ODS caching on.
<asp:ObjectDataSource ID="ODS" ... EnableCaching="true" />
This way the GetList will be called only when new data is needed. Post backs to pages that already had data retrieved will use the cached version and not call the GetList.
Or move your DataPager out of the ListView and set the PagedControlID property.
Actually you should be using the OnSelecting event.
What happens is that ObjectDataSource calls the method SelectMethod twice
First time it gets the data.
Next time it gets the count.
So I think you have to implement the OnSelecting event
<asp:ObjectDataSource ID="ODS" runat="server" SelectMethod="GetList" SelectCountMethod="GetListCount"
OnSelecting="ods_Selecting">
TypeName="Website.Test" EnablePaging="true" />
and then cancel the event when the ObjectDataSource tries to call the count method.
protected void ods_Selecting(object sender,
ObjectDataSourceSelectingEventArgs e)
{
if (e.ExecutingSelectCount)
{
//Cancel the event
return;
}
}
You can look for full implementation as mentioned in the link below
http://www.unboxedsolutions.com/sean/archive/2005/12/28/818.aspx
Hope this helps.
I had a similar problem where it worked different depending on browser. IE one way and all other browsers one way.. Might not be the same issue as you have.
I solved it this way:
protected void DropDownDataBound(object sender, EventArgs e)
{
// Issue with IE - Disable ViewState for IE browsers otherwhise the dropdown will render empty.
DropDownList DDL = (DropDownList)sender;
if (Request.Browser.Browser.Equals("IE", StringComparison.CurrentCultureIgnoreCase))
DDL.ViewStateMode = System.Web.UI.ViewStateMode.Disabled;
else
DDL.ViewStateMode = System.Web.UI.ViewStateMode.Inherit;
}
I have a user control which contains some buttons and a placeholder. Those buttons cause controls to be added/removed from placeholder. Everything works fine.
Now I want to put this user control in a page, and wrap it in an updatepanel like so:
<asp:UpdatePanel ChildrenAsTriggers="true" ID="UpdatePanelFoo" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<grid:tablegrid ID="tablegrid_chapters" runat="server" SomeProperty="bar" />
</ContentTemplate>
</asp:UpdatePanel>
When I run the page, it's still doing a full postback when I hit one of the buttons inside the user control. What am I doing wrong, and how can I remedy this?
Update:
protected void Page_Init()
{
ScriptManager scr = ScriptManager.GetCurrent(this.Page);
Response.Write("EnablePartialRendering: " + scr.EnablePartialRendering);
}
Outputs "EnablePartialRendering: true"
Make sure you have EnablePartialRendering=true on your ScriptManager in the page.
Update
It looks like your UserControl has no events to be looking for...you have 2 options here. Move the UpdatePanel inside the UserControl .ascx so it can see the button events as children to rig up or add an event for it to see, to do that try something like this:
public event EventHandler Click;
void btn_del_Click(object sender, EventArgs e)
{
if (NumberOfRowControls > 0)
{
var rowToWhack = panel_rows.Controls.Children().Single(x => x.ID == "myrow" + (NumberOfRowControls - 1));
panel_rows.Controls.Remove(rowToWhack);
NumberOfRowControls--;
}
if(Click != null) Click(this, e);
}
void btn_add_Click(object sender, EventArgs e)
{
var row = NewRow(NumberOfRowControls);
panel_rows.Controls.Add(row);
if(Click != null) Click(this, e);
}
And update the UpdatePanel to be looking for it:
<asp:UpdatePanel ID="UpdatePanelFoo" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<grid:tablegrid ID="tablegrid_chapters" runat="server" SomeProperty="bar" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="tablegrid_chapters" EventName="Click">
</Triggers>
</asp:UpdatePanel>
Make sure you add a ScriptManager as well to the page, otherwise there's no UpdatePanel functionality.