Custom Server Controls :: How To Custom Controls Derived From Existing Controls - Overriding Default Property Values
Nov 15, 2010
I have some (probably very basic) questions about developing custom controls. I am wanting to derive a set of button controls, and the first one I have started on is a "DeleteButton", that has a additional property (DeleteConfirmationText) that is built into the OnClientClick attribute. To get that added, I overrode the Render method as follows:
[Code]....
This all works well. Now, I will add some logic to make sure that there is some text in the DeleteConfirmationText property, but that isn't the intent of my question.
What I am also wanting to do is to override some of the default property values, so I added that to the default constructor:
[Code]....
Now, in the designer in VS2008, and I look at the properties for the control, there isn't a default value shown in the "Properties" section, and the Causesvalidation still shows the underlying classes default value of "True". As well, in design mode, where the GridView control that containse my DeleteButton control would be displayed, there is an error box "There was an error rendering the control. 'Are you certain you want to delete this attorney?' cound not be set on property 'DeleteConfirmationText'. Here's the markup where I am defining the deletebutton control:
I have created a class which inherits the HyperLinkField. I need to find the data values of the fields specified in the DataNavigateUrlFields property. I have not been able to figure out how to do this.
Iam developing a custom checkbox control deriving from the 'compositecontrol' which i need to use it for a composite control purpose.
public class TngCheckBox : CompositeControl {
i have written the required properties which are working fine except the "checked" property. here is my code for 'checked' property. i tried both the below ways (commented one and not commneted) . the problem is the 'checked' value is not setting the value at the get set part of the property.its assigning the value at the design time , but when i check and uncheck its not updating the property value.which is resulting me wrong .
Iam developing a custom checkbox control deriving from the 'compositecontrol' which i need to use it for a composite control purpose.
public class TngCheckBox : CompositeControl {
i have written the required properties which are working fine except the "checked" property. here is my code for 'checked' property. i tried both the below ways (commented one and not commneted) . the problem is the 'checked' value is not setting the value at the get set part of the property.its assigning the value at the design time , but when i check and uncheck its not updating the property value.which is resulting me wrong .
I have a custom control, inherited from Button. This is the class definition for the control and 2 properties:
[Code]....
I show you 2 properties, only to illustrate the problem.
as you see Aplicacion property is of a custom type Sistema, and Roles property is of type List<UserRol>.
The Aplicacion property is rendered well, this way:
[Code]....
The problem I have is with List<UserRol>. I couldn't get it to be rendered. I expeect to be rendered this way:
[Code]....
Finally, this is the TypeConverter and Editor definitions for the list:
[Code]....
The UserRol class is a typical class, without any special attributes.
I have discovered that when I use the custom editor for Roles property, the collection is not persisted. When I use the default editor for the collection, the collection is persisted.
I have created a custom control and I intended to assign some attributes which is not necessary to implament.
I also assign default value for them but I am getting System.NullReferenceException error.
Here is my CC's attibute code;
public class ApplicationModule2010 : CompositeControl { [DefaultValue(true)] public bool AppFormOnLine { get { return (bool)ViewState["AppFormOnLine"]; } set { ViewState["AppFormOnLine"] = value; } } ...
also ı have written the below code for another attribute but its default value doesn't work as well;
[DefaultValue("Application is Offline ! Define an offline Text insted of this text !<br/><br/>TugberkUgurlu.Com")] public string OfflineText { get { return (string)ViewState["OfflineText"]; } set { ViewState["OfflineText"] = value; } }
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 want to know if it is possible to extend the properties of a button and possibly override the render() method?I know how to create a custom server control and that is not what I want to do.I have a lot of web application that need to inject some java script on the button render event based on a new properties value.So what I want to do is extend the properties and hook into the Render method of the button control that ships with .net, I want to do it this way then I can still use the default button control but am able to effect all of the buttons in all of the web applications by simply re-publishing them.Inheriting from the System.Web.UI.WebControls.Button class enables me to add the property but then I have to register the "new" control and I have to go and change all of the buttons in all of the web applications.
The user control has public properties named accordingly and the page has protected properties accordingly which I've verified have the desired values.
For some reason the values are always empty strings or 0s in the usercontrol, no matter what the page property is.
In my user control i have the label1,textbox1 and dropdown1, i can able to set the values and get for both label and text box. but how can i set the value for the drop down.
from the aspx.cs or aspx.vb
i will set the object of the control (Ex: usercontrol1234)
usercontrol1234.propText="This is text box" usercontrol1234.propLbl="This is Label "
Then how can i set for the drop down? i can bind the dropdown data either by dataset or datareader.But cannot able to figure out how to set the property?
It was my expectation that by default, the Title property would be stored in ViewState, but this appears not to be the case - the exception in RenderBeginTag keeps getting thrown on postback.
Am I being thick? Do I need to explicitly store properties in ViewState?
But I am not able to find the correct syntax.I tried it without an editor and returning the type "Color", but that just generates a dropdown with all of the known color names for the property. I would like the color picker to appear which allows you to see the colors and pick one.
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?
I'm creating my first server control, and have it working where I can set up an enum and the user can set a property's choices, based off of that enum. But I'd like it to pull records from a database and populate the list of choices for the property from a database. This would allow me to add a new "Host System" to the database, and the other designers wouldn't have to get a new copy of the dll.
I have a site using eight (so far) custom web user controls and two of them have started misbehaving in design view. When designing the control itself some (in one control) or all (in the other) regular controls (labels, text boxes, etc.) disappear from the design view surface. They can still be seen in the source view and if the control is hosted on a regular .aspx page the control displays properly. The code window recognizes all controls in the objects dropdown list and I can write appropriate code. The controls run properly on their hosted pages.
If I switch to Split view and select controls in the source view panel a very small area od the design surface becomes selected (like one pixel for any of us who remember programming old DOS applications with 80-column screens) but no controls can be seen.
In short, the controls work in every respect except that I cannot see all or part of the design surface in Design view when editing the controls directly.
I've double-tripple checked the source code for anything that may be causing this and just don't see anything. (The controls aren't that complicated.)
I have created a user control that has a gridview. During binding I set some common properties like height and width. To do so, I have created public properties. I have created the public property so that user can also set the height and width themselves. But if user didn't specify then I use my defaults.
My problem is that user settings are always overridden by my default settings. I want to set the default values as the control is rendered on the page and then if user apply his settings then it shold override. Which event/method is best on user control to jandle such scenario? Where should I write the code to call my default settings so that it is first thing that happens? What is the user control life cycle?
I have a custom server control inheriting from CompositeControl. It consists of two RadioButtonlist controls that are rendered side by side in an html table. The number of ListItems in each RadioButtonList is not known until runtime. Depending on how many items each list contains, the RepeatColumns property of each list is set differently. To do this in the handler for the ItemDataBound event I need to get the count of ListItems in each RadioButtonList. How do I expose the Items.Count property of each internal RadioButtonList as a top-level property? I tried using a getter to return the count but this generates a compile-time error to the effect that the count cannot be assigned to--even though I have not created a setter.
Similarly, in the handler for the Submit event, I need to get the ClientID of each internal RadioButtonList to pass to a method that checks for data changes. How do I expose the ClientID of each component RadioButtonList as a top-level property?
I can of course index the Controls collection of the composite control to access the child control and read its properties--but that defeats the whole point of making a complex, independent custom server control.
Iam developing a custom server control of radiobuttton. it is working fine with the all the properties i wrapped except the grouping . somehow the grouping is not working .
