Web Forms :: Reference A Elements Of One Control From Other?
Sep 16, 2010
how user controls can communicate with each other within an asp.net application. I am facing many obstacles at the moment regarding this problem. For example, is it possible to set the visible property of a panel on one user control based on what happens in another?
Another example would be: Can I set the text of a label in one control to be the value of some other property from another control's class like.... Me.PreContentColumn.ColumnID = LocalProduct.PreContentColumnId.
I just found out that there is sort of a neat control called the "Menu-control"..but the thing is that I actually whould need my menuitems to contain more then just a plain text link..
I whould need it to out put something like this as my HTML:
[Code]....
This since I whould need to style my menuitem abit different..is this possible..and how?
I wonder if there is anyway to actually add a HTML element before or/and after the actuall <a>-element thats rendered by the Menu control. For instance I whould like my out put HTML to look like
I have...a dynamic populated select box several input boxes a submit button form fields are loaded initially using cookies several dynamic populated divs
I want... start loading the content of my DIVs after all FORM elements have been loaded completely (= filled with data, select boxes are populated)
I have created an asp.net application which contains a user control. Within the application this control works fine. I have then moved the control into a separate "control library" project. When I try to load the control from the control library I find that the asp elements defined in the ascx for the control are not instantiated - i.e. I get a null reference exception in the Page_Load event handler. The only changes that I have made to the original application are to reference my control library and to change the <%@ Register statement in the loading page to reference the control library dll:
[Code]....
Do I need to do something else to get the user control to initialize itself correctly?
I just recently started messing around with .NET (converted over from PHP) and I'm really enjoying it. I've created a test site for some friends at work and it works great. But I've been slowly converting the pieces of the site into user controls. I've moved some DataGrid elements to user controls for their specific purposes, and now I'm working on the main page (I'll attempt to copy the code below).
So pretty much this control displays:
1. An error panel
2. A podium panel (gold, silver, bronze) medals
3. A cake podium (the person who gets last place)
Before I moved this to a user control it worked perfectly. The Image files were updated from the SQL results. Believe me, I know it's not optimized so lets skip over that part. But when I view the dev site, the images are showing up as blank or broken. Nothing I do to change one of the ASP elements in the user control are being updated. I have a Response.Write sitting there just to ensure that the events are being caught and handled correctly.
I've got a custom ASP.Net web user control I've built; done this enough times before but this one is misbehaving and I can't spot why.
Where the calling page includes the user control directly in its markup, all is well and the control behaves as expected.
However if the page adds this particular control dynamically (to a placeholder in the master page, which is what's calling this whole thing) the elements within it stay firmly NULL - nothing from the user control gets written to the client at all, including static content within the user control.
I have a web user control menu of page. Now I want HOME (which is an hyperlink text) in menu to be Bold at the time default.aspx Loaded (Load event)! How can I do that If any one can provide code! I am using VB .Net at back.
I'm getting an "Object Reference Not Set to an Instance Of An Object Error" in a Web User Control that I've created when referencing any control in the Code Behind. Intellisense reports that the control exists in the aspx, but whenever I build and run I get that error.
I am trying to assign user control from another user control ..first time its binding control successfully but when we refresh the data its giving error
saying "Object reference is not set an instance".
how to refresh data from another user control ...
My senerio below :
1 Aspx page
2. User control
calling usercontrol databinding method from aspx page but once it get refreshed ,not allowed to bind it again..
i am trying to enter a value into a texbox that is placed inside a user control called CollectionRequest. i have referenced this user control in my code behind and created an instance of it but i seem to get the above error when i try to enter some manual text. code as follows:
protected CollectionRequest collReq; protected void Page_Load( object sender, EventArgs e ) { collReq = (CollectionRequest)LoadControl("~/CollectionRequest.ascx"); TextBox _txt_address = (TextBox)collReq.FindControl("txt_Address"); _txt_address.Text = "thisi is an address"; control has been referenced in source file <%@ Reference Control="~/CollectionRequest.ascx"%>
i am caling this code in my Approval.ascx.cs code. both the user controls are displayed together in the default.aspx page one above the other.
MSDN documentation says that the ScriptManager class is part of the System.Web.UI namespace and I see that I can create a ScriptManager object programmatically. However, I don't see the ScriptManager control on the front-end. Do I need to reference the Ajax Control Toolkit dll in order to have access to control?
I am having a problem with rendering a menu control inside a server control. I am getting an error in the RenderContents override method when I try to render the Menu Control. The error I am getting is an Object Reference error. The code is below...
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="test.ascx.cs" Inherits="UserControls_test" %> <p id="XXX">aaa</p>
and here is the contents of my test.ascx.cs file:
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class UserControls_test : System.Web.UI.UserControl { protected void Page_Load(object sender, EventArgs e) { this.XXX.InnerHtml = "BBB"; } }
I get an error when I refer to the id, "XXX" (underlined above) in code behind which reads: 'UserControls_test' does not contain a definition for 'XXX' and no extension method 'XXX' accepting a first argument of type 'UserControls_test' could be found (are you missing a using directive or an assembly reference?)
I have tried XXX.InnerHtml and I have tried this.XXX.InnerHtml and get same problem.
How do I successfully refer to ID'ed HTML elements in code behind?
I have one Custom Control! I add reference in pages Like Below <%@ Register TagPrefix="cus" Namespace="Controls" %> at Run time There is No error ! Error Shown at deploy Time Unknown server tag 'cus:GridHeaderFilter'. My custom control is in App_Code folder With Name GridHeaderFilter.vb So How To add Or Register This Custom Control In web confige File
my MasterPage I have a label that reflects the name of the module that the user is currently in. I change the label text accordingly using the following ..
Instead of placing this method in the code-behind of every page, I want to put it in a single class and call it accordingly. I thought of using a static class but do not know how to reference the MasterPage.Can I use a static class? or do I place the method in the code-behind of one page and call Object.Method from the other pages?
I am stuck into a problem, i have a user control ProductListing.ascx that contains ListView binded to an object datasource, SelectMethod and SelectCountmethod are provided as well. Everything works fine but the problem started when i add another user control declarativlly Filter.ascx in the productListing.ascx. I want to assign value to a public property MaxPrice in Filter.ascx. I am trying to set this property in the SelectMethod of ObjectDataSource. Usercontrol "Filter.ascx" throws null reference exception when i try to set its MaxPrice Property.
I tried to acced the usercontrol in Databind method of ListView , it is accessible here but viewstate is empty at this point, i saved the value in viewstate in SelectMethod of objectDatasource but i cant access viewstate in ListView Databind. Its empty. Its a simple code and no rewriting to viewstate elsewhere.
Important: My Codebehind files are in a seperate project and .ascx files in seperate project
I'm trying to programatically reference a FileUpload control which I have within an ItemTemplate. I get a 'Name FileUpload1 is not declared' error message. Code below:
I wish to know if it is possible to directly reference a control's value within an SQL Command? I remeber seeing something that caught my attention at one time, but I can't seem to remember where I found it. I am just trying to see if this method could work without having to declare parameters. Here is a sample idea of what I am trying to use:
I am trying to implement adding a new record using the Gridview footer.
I have an example that works finethat I got from [URL]
My situation is a little different .. as I am using master page and the Gridview is in a page derived from the master page.
I have tried:
Dim txtNewName As TextBox = DirectCast(GridView1.FooterRow.FindControl("NewName"), TextBox) "NewName" is the ID of the textbox in the footer of the Gridview.
When I try referencing ... txtNewName.Text ... it returns a null value.
There must be some trick to referencing this .Text value when using the Gridview that is within a Content Place Holder that results when using a page that was created using a master page.
I am attempting to access a textbox control on a master page from a code behind base class but having problems. I have 3 levels of master pages. m1.master is the master page for m2.master which is the master page for m3.master.m3.master has a textbox as shown below
i have found out a way to find controls on content pages by using
var txt = $('input[id$=TextBox1]'). But how to access html elements like "<p>" tag and others in jquery when the html elements are in content page only.
I have a custom control that is based off the gridview control located at: here The control is basically a gridview that automatically creates a column of checkboxes that can be used to "check" individual rows in the gridview. During the gridview's "CreateColumns" event, the "checkboxcolumn" is created dynamically. The checkboxcolumn also contains another checkbox in the header that is used to "select/deselect all" checkboxes in the column. Since the gridview does not automatically remember the state of the checkboxes in the checkboxcolumn on postback, I added a method to the control called "SaveCheckBoxState" which stores the indexes of the checked rows in Viewstate, and then I modified the "OnRowDataBound" event to check the Viewstate and reset the checkboxes based on the Viewstate.
I then added a call to "SaveCheckBoxState" in the gridview's OnSorting and OnPageIndexChanging events. This works great so long as I'm sorting or changing pages. However, I need it to update the viewstate everytime someone clicks or unclicks one of the checkboxes. At this time, the checkboxes are rendered with an onclick event that calls some javascript to highlight the row, or in the case of the checkbox in the header, to select/deselect all checkboxes. I need to call the "SaveCheckBoxState" method from the javascript used by the customcontrol, or I need to find a way to modify viewstate from javascript and perform the same action as "SaveCheckBoxState".
I've tried adding the "SaveCheckBoxState" to the onclick event declaration in the checkboxes, but when run, it simply tells me that the method is undefined. It doesn't exist in the parent page, and I don't think I should have to make an event for the parent page to pass the click to. It seems to me this should be all self contained within the custom control. Does anyone know how I can acheive this? Here is the code for the gridview OnPreRender event where the onclick event of the checkbox is set:
protected override void OnPreRender(EventArgs e) { // Do as usual base.OnPreRender(e); // Adjust each data row foreach (GridViewRow r in Rows) { // Get the appropriate style object for the row TableItemStyle style = GetRowStyleFromState(r.RowState); // Retrieve the reference to the checkbox CheckBox cb = (CheckBox)r.FindControl(InputCheckBoxField.CheckBoxID); // Build the ID of the checkbox in the header string headerCheckBoxID = String.Format(CheckBoxColumHeaderID, ClientID); // Add script code to enable selection cb.Attributes["onclick"] = String.Format("ApplyStyle(this, '{0}', '{1}', '{2}')", SelectedRowStyle.CssClass, style.CssClass, headerCheckBoxID); // Update the style of the checkbox if checked if (cb.Checked) { r.BackColor = SelectedRowStyle.BackColor; r.ForeColor = SelectedRowStyle.ForeColor; r.Font.Bold = SelectedRowStyle.Font.Bold; } else { r.BackColor = style.BackColor; r.ForeColor = style.ForeColor; r.Font.Bold = style.Font.Bold; } } }
