I am trying to develop a very simple templated custom server control that resembles GridView. Basically, I want the control to be added in the .aspx page like this:
[Code]....
I know that what I want to achieve is pointless and that I can use DataGrid to achieve it, but I am giving this very simple example because if I know how to do this I would be able to develop the control that I need.
I am fairly new to asp.net programming. I found this custom control that uses ajax to update the contents of the control and it is working perfectly. However, I need to access some of the asp.net labels and images in the databound event so I can set their values/properties appropriately, and am not sure how to go about adding additional code or accessing these in my custom control (I have been googling endlessly with no results). My code for the custom control is below.
Imports System
Imports System.Text
Imports System.IO
Imports System.Collections
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports Microsoft.VisualBasic
Namespace myControls
Public Class AjaxDivView
Inherits CompositeDataBoundControl
Implements ICallbackEventHandler
Private _itemTemplate As ITemplate
''' <summary>
''' The ItemTemplate is used to format each item from the data source.
''' </summary>
<TemplateContainer(GetType(DivViewItem))> _
<PersistenceMode(PersistenceMode.InnerProperty)> _
Public Property ItemTemplate() As ITemplate
Get
Return _itemTemplate
End Get
Set(ByVal value As ITemplate)
_itemTemplate = value
End Set
End Property
''' <summary>
''' Register Javascript
''' </summary>
Protected Overrides Sub OnPreRender(ByVal e As System.EventArgs)
'Register Refresh Function
Dim eRef As String = Page.ClientScript.GetCallbackEventReference(Me, Nothing, "AjaxDivView_Result", "'" & Me.ClientID & "'", "AjaxDivView_Error", False)
Dim refreshFunc As String = "function AjaxDivView_Refresh() {" & eRef & "}"
Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), Me.UniqueID, refreshFunc, True)
MyBase.OnPreRender(e)
End Sub
''' <summary>
''' Iterate through the data items and instantiate each data item in a template.
''' </summary>
Protected Overloads Overrides Function CreateChildControls(ByVal dataSource As System.Collections.IEnumerable, ByVal dataBinding As Boolean) As Integer
Dim counter As Integer = 0
For Each dataItem As Object In dataSource
Dim contentItem As New DivViewItem(dataItem, counter)
_itemTemplate.InstantiateIn(contentItem)
Controls.Add(contentItem)
counter = counter + 1
Next
DataBind(False)
Return counter
End Function
''' <summary>
''' Render this control's contents in a Ul tag
''' </summary>
Protected Overrides ReadOnly Property TagKey() As System.Web.UI.HtmlTextWriterTag
Get
Return HtmlTextWriterTag.Div
End Get
End Property
''' <summary>
''' Render my contents to a string and send the result back to the client
''' </summary>
Public Function GetCallbackResult() As String Implements System.Web.UI.ICallbackEventHandler.GetCallbackResult
Dim builder As New StringBuilder()
Dim sWriter As New StringWriter(builder)
Dim hWriter As New HtmlTextWriter(sWriter)
Me.RenderContents(hWriter)
Return builder.ToString()
End Function
''' <summary>
''' Whenever I get called through AJAX, rebind my data.
''' </summary>
Public Sub RaiseCallbackEvent(ByVal eventArgument As String) Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
Me.DataBind()
End Sub
Public Class DivViewItem
Inherits WebControl
Implements IDataItemContainer
Private _dataItem As Object
Private _index As Integer
Public ReadOnly Property DataItem() As Object Implements System.Web.UI.IDataItemContainer.DataItem
Get
Return _dataItem
End Get
End Property
Public ReadOnly Property DataItemIndex() As Integer Implements System.Web.UI.IDataItemContainer.DataItemIndex
Get
Return _index
End Get
End Property
Public ReadOnly Property DisplayIndex() As Integer Implements System.Web.UI.IDataItemContainer.DisplayIndex
Get
Return _index
End Get
End Property
Protected Overrides ReadOnly Property TagKey() As System.Web.UI.HtmlTextWriterTag
Get
Return HtmlTextWriterTag.Div
End Get
End Property
Public Sub New(ByVal dataItem As Object, ByVal index As Integer)
_dataItem = dataItem
_index = index
End Sub
End Class
End Class
End Namespace
Context
I'm putting together a templated, databound control. Presently it works with the following syntax...
<cc:ItemChooserControl ID="ItemChooser" runat="server">
<TitleTemplate>
<h4><%# DataBinder.Eval(Container.DataItem, "DisplayName") %></h4>
</TitleTemplate>
</cc:ItemChooserControl>
Problem
What I would like though is that the shorter, simpler Eval would work instead.
<h4><%# Eval("DisplayName") %></h4>
What I get however when using straight Eval is an error:
Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.
Code
I'm databinding to a custom HtmlTableCell...
public class TitleTemplateTableCell: HtmlTableCell, INamingContainer
{
private object m_DataItem;
public virtual object DataItem
{
get { return m_DataItem; }
set { m_DataItem = value; }
}
}
With the following custom DataBind (non-related code removed)...
foreach (object dataItem in dataSource) {
TitleTemplateTableCell title = new TitleTemplateTableCell();
TitleTemplate.InstantiateIn(title); // TitleTemplate is the template property
title.DataItem = dataItem;
title.DataBind();
}
Basically, I have a custom templated control with a custom data container class. When a developer adds an instance of my control to a page, they can define the controls in the LayoutTemplate however they like, as follows:
<ml:MyControl id="MyControl1" runat="server">
<LayoutTemplate>
<span><%#Container.ErrorMessage%></span>[code]...
I would like my control to automatically move the "ml_errormessage" (databound content from Container.ErrorMessage - hard coded token in the property) to be a class of its containing element to make it easier for jQuery to use a selector to find the element and dynamically insert the error message client side. More importantly, I would like it moved out of the way so the class name doesn't get replaced by the content and jQuery can find it as many times as it needs to during the page lifecycle. In other words, I would like the output to look like this without the developer changing the input template or resort to using custom controls in the template:
<span id="MyControl1"><span>
<span class="ml_errormessage"></span>
</span></span>
I would like to move the value using the controls collection rather than resorting to string parsing of the output, if possible. However, when I interrogate the collection in an override of OnPreRender, the control in the template looks like this in the debugger:
{System.Web.UI.DataBoundLiteralControl}
System.Web.UI.DataBoundLiteralControl: {System.Web.UI.DataBoundLiteralControl} [code]...
As you can see the "ml_errormessage" value is nowhere to be found. Upon analysis of the DataBind event of the Control class using Reflector, I see that it delegates the binding behavior to each control. In other words, each control handles its own databinding. However, since I have no way of knowing in advance what control types will be in the template, how can this change be done?
Note: an acceptable alternative would be to add a new HtmlGenericControl (span) in the exact spot where the "ml_errormessage" is and add it as a class to this new control.On a side note, is there an easy way to get the control's output to indent for easy reading during debugging?
I dont want to use asp.net's TreeView control. I want to create a custom template databound control with multi template support like -
<asp:MtNavigationControl>
<ItemTemplate>
...
...
</ItemTemplate>
<SelectedItemTemplate>
...
...
</SelectedItemTemplate>
<ParentItemTemplate>
...
...
</ParentSelectedItemTemplate>
<SelectedParentItemTemplate>
...
...
</SelectedParentSelectedItemTemplate>
</asp:MtNavigationControl>
My data is like -
class Employee
{
string EmployeeName
List<Employee> Employees
}
Does anyone know how to accomplish it?
I am trying to build a custom composite control, which allows me to add custom content to each child control. It's a similar concept to what you have with a GridView and TemplateColumn. The markup used to place the control on the page would end up being something like this:
[Code]....
I have the code below, which allows me to put that markup on the page without throwing any errors, and it renders all the correct HTML, except it doesn't render the contents of the ColumnTemplate. I have replaced the Render() code with a comment because it's quite long winded and doesn't add anything important here:
[Code]....
I have tried to follow examples on MSDN and other forums but I can't make this work. I think I'm missing the code to render the contents of the template, but I don't know how to hook that up.
I have a templated user control with single instance template attribute. It works great for everything except the following scenario:
[Code]....
The folder selector uses a tree view that allows people to select a folder, its FolderSelected event works perfectly and the file selector updates with the files. The file selector has a repeater that lists the files in the selected directory. It has a linkbutton for each of the files so that the user can select a file. The problem is that the ItemCommand event of the repeater doesn't fire when the file name is clicked on. The page performs the async postback like it should, but in debug, the method to handle the itemcommand event is never hit. On the same user control to select files there is a button that the user can add files to the folder. When it is clicked, the event DOES fire and the file is added and the control refreshes in the update panel, everything perfect. It seems that because the linkbutton is already in a templated control (which is in a user control, in a templated control), the event isn't firing correctly. I am confused as to why this should be a problem, especially since all the other events (even the custom ones) fire as long as they aren't in another templated control. Since the code is complicated, I didn't want to post it all here.
here's a situation and I would appreciate your response.
I have programmatically created the Wizard control:
Page_Load(obj s, evargs e)
{
Wizard ClaimDetailWizard = new Wizard();
foreach(int item in selectedItems)
{
//create new step
//added custom control to new step
//add step to wizard
}
//added wizard to a placeholder on a page
}
Based on List I get from Session i added new steps to my wizard To each step I had added a custom control
Each custom control in tern contains another custom Gridview Control in it.
So here's the problem when the page loads for example for two steps. All is good Wizard does what it's supposed to do.
But when I try to use sorting or paging in that custom Gridview. Somehow it displays the gridview I should see in the next step of the wizard.
Also what I'm noticing through debugging. Is that when I press next in the wizard I go back to the original page where I do all of the code specified above, and it recreates the wizzard. But it goes to the next step. Is this the way wizard supposed to work? Just doesn't seem very efficient.
I want to be able to do something like this
<test:TabControl id="" runat="server"....>
<ItemTemplate>
<tabItem label="tab1" />
<tabItem label="tab2" />
</ItemTemplate>
</test>
The idea being here is that the only acceptable items in "ItemTemplates" are the tabitem types. There are many asp.net controls that use this, for example the ScriptManager class only allows you to specify certain types of objects under its various collections. Maybe thats the key to this.. I want to add a collection as opposed to a template. The idea is that in code I will then iterate over each "tabItem" and create the tab as I want it to look (probably rendering div's etc). Ive had a look at most of MSDN link on how to create templated controls but it doesnt seem to do exactly what I want it to. Would be grateful for some assistance.
i've created a webform with one gridview having connected with the database using datasource. i.e password database with three colomn .
now want to insert the custom dropdown button using server control for each column.
when i select the dropdown list the list should display the value as required.
e.g if i click the uname dropdownlist then it should show the list of names.
if i click on pwd dropdownlist then it should show the list of numbers.
if i select any one of the value in the dropdown list then it should insert into the
database.
can i get code on this type of question...?
Why custom Gridview control not render html properlies under <Columns> properly in Visual Studio 2005?
For example:
[code]....
I'm working on a website to showcase some of my bird photography, using ASP.NET 2.0 and C# with a SQLServerExpress backend.What I have right now is a ListBox bound to my database that displays a list of common names of birds and when the user clicks on an item in the listbox the main image on the page is changed to the image for that bird. For style reasons I want the listbox to always be a fixed size and because I specify the size (using CSS) a vertical scrollbar appears. My problem is that I want to provide my own images of arrows that go above and below the box such that when the user hovers over an arrow the box scrolls slowly and when the user clicks an arow the box scrolls quickly. Finally, my main problem is that I want to get rid of the ugly default vertical scrollbar that comes with ListBox.
Can you guys help me figure out how to do this? I don't mind using a different control other than ListBox as long as it is available in ASP.NET 2.0 and as long as it can be bound to my db. I also don't mind using JavaScript (which I'm sure I'll end up doing for the hover effects). Right now I'm fooling around with subclassing the ListBox control but I've never subclassed a control before so I'm somewhat clueless.
I have a DetailsView control bound to an ObjectDataSource within a User Control (.ascx). It appears that the DetailsView.OnDataBound event is being fired on every page load or postback.
I do not see this behavior with a similiar DetailsView directly placed on an aspx page.
Hope this is the correct forum for this question. I am using VWD 2010 an have a web project and get the following error upon execution:
Parser Error Message: Unknown server tag 'custom:AjaxValidator'.
My code is as follows in the .cs file:
[Code]....
[Code]....
I want to created a Custom Server Control (Inherited from GridView).
On the page, the GridView is DataBound to a DataSet, so I do not know at design time what columns will be present in my GridView.
Now, what I want to do is, to add a textbox in every Cell for the GridView Header row, and those textboxes will control column filtering.
I have a custom control which inherit from the Table class and in the constructor, it takes a an integer as an argument. There is no empty constructor.
Is there a way for the user to set that variable in the properties window after they drag the control onto a form.
I know some .NET controls, you can set the source for the parameter to different things like another control's property, QueryString using just the properties window.
Right now, I have to create the control dynamically. I read the query string and then created the object.
I'm trying to extend GridView control following these steps:Create a namespace in an empty Visual Basic file: mycontrols.vb
[Code]....
Register it in the WebForm I want it to be
[Code]....
Create the control in my WebForm:
[Code]....
I get an error as tag prefix unknown, and in my code behind file, the control doesn't recognize the primitive GridView properties and methods.
I'm trying to extend de GridView control with a Custom Server Control, I'm doing ok with extended properties but when I get to methods that need to re-apply or modifiy the DataSource I don't get any data in the grid, though the SQLDataSource actually retrieve data. Here is my MyGridView.applyFilter() method, which should filter the data but actually shows an empty GridView, but as I sayed, the DataSource has data. I try to find (FindControl) theSQLDataSource of the GridView (Me) and modifiy its paramters, thenDataBind Me to apply the changes...
[Code]....
What am I doing wrong? why is the gridview empty?
How to change the values in gridview on text change of templated control without databind again?the value of templated text boxes should change If i change the value of one of the templated textbox then accordingly(By mathematical calculations) the vlaues of all tempated textboxes should also change.
View 7 RepliesI need to develop control (template or user) which must have subtags with some items.
For example :
<SomeControl runat="server" id="scTest">
<column1>TestColumn1</column1>
<column1>TestColumn1</column1>
<column1>TestColumn1</column1>
</SomeControl>
This control may contain some other web server controls such as GridView.I need explanation of experienced developers, how to do that - take me to the right way
i am new to technology so go easy on this post according to what i read from web there are 3 type of custom server controls 1 superclass2 composite 3 renderedi found video tutorial for superclass custom server control but couldnt find video tutials for other 2.lease forward me link for composite and rendered custom server controls video tutorial
View 1 RepliesSo I finally managed to create a control which basically shows a bunch of Panels with an extra property. I use it like this:
[Code]....
This renders fine and shows the text in the TabPanel controls. However, when I replace the plain text with something a little more exciting, say an UpdatePanel so it looks like this:
[Code]....
Then I get this weird error:
Page cannot be null. ensure that this operation is being performed in the context of an ASP.NET request.[InvalidOperationException: Page cannot be null. ensure that this operation is being performed in the context of an ASP.NET request.] System.Web.UI.UpdatePanel.get_IPage() +647672 System.Web.UI.UpdatePanel.Render(HtmlTextWriter writer) +20 SP.adminonly_reports_loginreport_aspx.__RenderTabPanel1(HtmlTextWriter __w, Control parameterContainer) in D:....eport.aspx:37 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +115 System.Web.UI.WebControls.WebControl.RenderContents(HtmlTextWriter writer) +13 System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +42 TabPanels.TabPanelHolder.Render(HtmlTextWriter w) in D:e4Webwwwrootlms_workingTabPanelsTabPanelsTabPanelHolder.vb:146 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240 System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +253 System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +87 System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer) +53 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240 System.Web.UI.Page.Render(HtmlTextWriter writer) +38 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4240
If I take out the UpdatePanel and replace it with an ASCX control I made that simply puts database data into some DropDownLists, like this...
[Code]....
Then the page loads, but the data is not loaded into CustomerUserList1, and the dropdownlists within it are all blank. CustomerUserList1 has worked fine for years when used directly in a normal Panel/Page UpdatePanel.
[Code]....
created a Custom Textbox Control that is intended to be a "masked date" textbox, so that I can handle different ways a user might enter in a date and make it work no matter what.I did this by creating a custom control with 3 separate Textboxes one for month,one for day one for year,then do some handling for different things that could be entered and it would all work.
The problem I am having is,when I add this control to the page,if I do an alert to check the Text value of the custom control it just gives me "[ServerControl1]" even if I enter in a date.
I tried doing an AutoPostback after entering so that it would refesh the Viewstate to have the values of the textboxes but the control doesnt seem to actually postback, even though I have it enabled.accessing the Textbox value after someoen
has entered a date?first custom control I have created and have been using google.
My Server Control Code is as follows:
[Code]...
i'm developing a webusercontrol, that has very properties, properties are of custome types (not primitive), so i want user can edit properties in grid property. i want something like gridview here is a portion of my code:
[Code]....
[Code]....
i have created a new user control who contains a gridview so, my prolem now is that i want show all the property of the gridview included in the control, but i want not write like this:"Usercontrol1.GridView1.Datasource=...." but i want write "Usercontrol1.DataSource=..." and this also for other controls how can i do this?
View 1 Replies