So essentially, I have a custom user control called ExcelDisplay. I try to drag it over in visual studio from the toolbox into my webform in the same project and I get a missing method exception. At one time the constructor was parameterized, but I changed it after deciding it was a bad design idea.
It looks like it is saying the constructor is missing, but its obviously there.
My winform to house the control is empty with the exception of the autogenerated code visual studio puts there.
The code for my ExcelDisplay's constructor looks like this.
namespace STS_Console.UserControls
{
public partial class ExcelDisplay : UserControl
{
public ExcelDisplay()
{
InitializeComponent();
DataDisplay.Columns[0].HeaderText = "Data";
//debug
string x = DataDisplay.Columns[0].GetType().ToString();
x.ToString();
}
The error message is this.
So that error occurs when do I drag and drop in the designer like this
Anyway so that is my problem. I am not sure what is causing it or how to fix it. I would be glad to post additional code upon request.
You should put your user controls in a class library of their own. For the designer to work, it needs a compiled version of your user control. If you cannot compile your user control before you compile your form, you will get into all kinds of trouble.
Rebuild Solution fixed it for me, although if your making regular changes to your user control, you should put them into a separate project.
My particular problem, was a user control, within a user control.
Related
I've created a custom user control, that is essentially a custom button within my windows form app. I managed the redirect of the click event to using the following code:
Control[] customButtonControls = button.Controls.Find("buttonInUserControl", false);
Button nestedButton = (Button)customButtonControls[0];
nestedButton.Click += new System.EventHandler(this.button_click_handling_function);
I've appended this to the Window_Name.Designer.cs file below the generated code for the control with my button_click_handling_function being defined in my Window_Name.cs file.
The issue is that when I then click back to the Window_Name.cs[Design] page, I am met with an error page. I will include screen shots to better show the errors. Basically it is a super unhelpful page. It tells me that I have an index out of range error on my Array, but the stack call makes no sense.
If I try to build my Solution, I am met with NO compile errors and my program acts exactly as intended. The click event triggers the function just as before.
Thanks in Advance.
Portions of the designer code are run at design-time. The index out of range error is probably because at design-time there are no controls found yet by that Find call so the array is empty. You are not checking for 0 length so when you de-reference it you get the error.
It works at run-time because at that point the controls have been instantiated.
The secondary problem though is you should not put things into the Designer.cs files since that code is auto generated by the designer and could be regenerated at some point and your added code lost. Put that code in the Window_Name.cs after the InitializeComponent call.
In my app namespace = DRT, I'm creating control classes (e.g., button, textbox) that derive fron their corresponding Windows control classes, e.g.,
internal abstract class DRT_Button_Abstract : Button
{
....
}
internal class DRT_Button_CancelSearch : DRT_Button_Abstract
{
....
}
internal class DRT_Button_StartSearch : DRT_Button_Abstract
{
....
}
All together I currently have 13 derived classes that derive either from one of my abstracts or from a Windows control class. After a successful build, I see my control classes (e.g., DRT_Button_CancelSearch and DRT_Button_StartSearch) on the Toolbox and I successfully drop them onto my main form. All is fine for a while, but ultimately, I'll go to open the main form.cs [Design] (i.e., the UI designer) and it will show the error The variable '{control property name}' is either undeclared or was never assigned. for some combination of my controls.
When I examine the main form Designer.cs file, the expected code for all the controls is present EXCEPT for the expected new statement. They are not present in the main form Designer.cs file. For example, I expect to see this.drt_Button_CancelSearch = new DRT.DRT_Button_CancelSearch(); but its missing
I've tried ignoring the error, proceeding to the UI designer windows to re-apply the lost controls, but the problem just repeats with the newly applied control
What the heck is going on? Is there a way to recover from this situation?
This is most likely a problem of the Designer not being able to clear/reload its cache. There is not much you can do. In the past I:
closed and reopened all designers that have user controls
put all the controls in a separate project (in the same solution)
put all the controls in a separate solution/Visual Studio instance and set a proper reference to the controls' dll (or even nuget package)
With the first two options I have had varying success. Reopening the designer is not very convenient and doesn't work.
That last option is the best but also the most annoying because every adjustment requires a rebuild of the project and update of the reference/package.
Also make sure that all controls that you create have public default constructors and function well when this constructor is used.
I was wondering is it possible to prevent Visual Studio from updating specific lines that are changed by me?
For example i have separate resource only project (images, sounds, etc). I change some lines in Form.Designer.cs and make so all images are loaded from resource dll. But once i update Form it self everything goes back to default and all resources that were used by form gets copied to Form.resx file.
How could i solve this?
Nope.
As stated in the begining of the file, the *.Designer.* is an auto generated file. It's rebuilt every time that the file it depends upon is saved, so you should never change any code there that you don't want to be messed.
It is preferable to separate the code that the form designer generates from the code that you want to have some control over. The order in which you need to address this code can then be handled within the constructor of the form. Example:
namespace FormTest
{
public partial class Form1 : Form
{
private Label PostAddedLabel;
public Form1()
{
InitializeComponent();
PostInitializeComponents();
}
private void PostInitializeComponents()
{
if (!this.DesignMode)
{
PostAddedLabel = new Label();
PostAddedLabel.Left = 100;
PostAddedLabel.Top = 30;
PostAddedLabel.Text = "The Post-added Label";
this.Controls.Add(PostAddedLabel);
}
}
}
}
We can simply design the form within the designer, after a successful design phase we then can MOVE the declaration, assignments and related code that we want to separate to the PostInitializeComponents method.
By using the !this.DesignMode decision, the form will show the separated controls in Runtime mode. When in designer-mode these controls will not be shown, assuring that the system will not affect these controls when designing the form.
In case you want to use this methodology also in usercontrols, try to embed the "IsDesignerHosted" method over "DesignMode" from the following article: DesignMode with Controls
Hope this answers the question?
No. Visual Studio does not "update" the Designer file, it deletes it and writes an all new copy. No possible way to do what you want.
You should add your code to your code behind. It's the same class.
I have created a custom data grid control. I dragged it on windows form and set its properties like column and all & ran the project. It built successfully and I am able to view the grid control on the form.
Now if i try to view that form in designer, I am getting following error..
Object reference not set to an instance of an object.
Instances of this error (1)
1. Hide Call Stack
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.GetMemberTargetObject(XmlElementData xmlElementData, String& member)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.CreateAssignStatement(XmlElementData xmlElement)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.XmlElementData.get_CodeDomElement()
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.EndElement(String prefix, String name, String urn)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.Parse(XmlReader reader)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.ParseXml(String xmlStream, CodeStatementCollection statementCollection, String fileName, String methodName)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomParser.OnMethodPopulateStatements(Object sender, EventArgs e)
at System.CodeDom.CodeMemberMethod.get_Statements()
at System.ComponentModel.Design.Serialization.TypeCodeDomSerializer.Deserialize(IDesignerSerializationManager manager, CodeTypeDeclaration declaration)
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.DeferredLoadHandler.Microsoft.VisualStudio.TextManager.Interop.IVsTextBufferDataEvents.OnLoadCompleted(Int32 fReload)
If I ignore the exception, form appears blank with no sign of grid control on it. However I can see the code for the grid in the designer file.
Any pointer on this would be a great help.
I have customized grid for my custom requirements like I have added custom text box n all. I have defined 3 constructors
public GridControl()
public GridControl(IContainer container)
protected GridControl(SerializationInfo info, StreamingContext context)
I have this problem all the time...it sucks.
[Ramble(on)]
Here is what I think I know:
When designing place the control on a form. Build and refresh often..this will let you know what change caused the designer to barf.
Close visual studio all the way an re-open....I cannot tell you how many times I have chased a designer error that was the designer being "stuck".
It is very important that you understand : The designer is really, really stupid...like bag of rocks stupid.
Any public fields or properties of custom object types will almost always cause designer confusion*. I find the following attributes will clear up most of these problems:
[Browsable(false)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
Public fields or properties without a default constructor will always cause designer confusion. When you drop a user control on a form the designer effectively creates the control..so any public object needs a clear creation path. I have found that the easiest way around this (read hack) is keeping the non-trivial custom classes private and expose public properties as a facade.
-- Did I say restart visual studio because sometimes the designer is "stuck" on an error that doesn't exist ?..I hope I did.
[Ramble(off)]
I hope some of this helps..
*designer confusion: Instead of showing your controls the designer shows you a useless error message that might or might not include the dire warning that it is protecting you from code loss...blah, blah.
It sounds like a NullReferenceException is thrown in your control's default constructor (the one without parameters). Obviously, this exception is only thrown at design time since you say it works at runtime. Do you perform any initialization code in this constructor, like data base calls or similar? Or do you use any instances which might not be available at design time?
It looks like the form-designer is trying to initialize the control. Yet, the property it is trying to initialize may have been removed from the UserControl. There are lots of way to troubleshoot this problem. I recommend you debug the control in design-time. It is the surest way to find the problem. Check out "MSDN Search" for "design-time control debugging" at http://social.msdn.microsoft.com/Search/en-US?query=design-time+control+debugging&ac=8
I had run in to the same error check whether your Windows Form class inherits from System.Windows.Forms.Form class as in Form1:Form Hope dis helps !!!!
I plan to add functionalities to TextBox with the following:
public class TextBoxExt : TextBox
{
protected override void OnKeyPress(KeyPressEventArgs e)
{
base.OnKeyPress(e);
}
}
The question is how can we use this TextBoxExt? Is there anyway to get this class onto the ToolBox so that we can just drag and drop it onto the form? If not, what is the best way to use the TextBoxExt?
Build you project with TextBoxExt, make sure it compiles ok.
With the form that you want TextBoxExt on, open the toolbox, right click and select "choose items"
Browse to you .exe or dll that you compiled in 1)
make sure that TextBoxExt has a tick next to it, press ok
TextBoxExt should appear in the toolbox, drag it onto your form
(There is another way of doing this, opening the designer file and renaming the instances of TextBox to TextBoxExt but manual editing of designer files can be considered hazardous by some)
I know this is super old question, but maybe still useful for someone else that has same problem like me - as it's still on the top Google :)
You might interest to use ToolboxItemAttribute (http://msdn.microsoft.com/en-us/library/system.componentmodel.toolboxitemattribute(v=vs.110).aspx).
I did this at my end to resolve the problem.
[ToolboxItem(true)]
public class PanelTitle : LabelControl {
// Whatever code to override LabelControl here...
}
Rebuild the solution and the extended control should be shown in the toolbox.
Any custom control in your project should show up in the Toolbox automatically. I have found that sometimes the controls won't show until you close a re-open Visual Studio. I assume the issue has something to do with caching of the contents of the Toolbox.
You need to add a constructor to your derived class.
public class TextBoxExt : TextBox
{
public TextBoxExt()
{
}
protected override void OnKeyPress(KeyPressEventArgs e)
{
base.OnKeyPress(e);
}
}
Your control should appear in the toolbox for your solution automatically. To have it appear for other projects, you have to do Choose Toolbox items, as others have said.
If you want to provide special design-time functionality, then you will also need to provide some additional designer related attributes and probably your own class derived from ControlDesigner.
I fell into this trap just a couple of hours ago.
I've got a .NET 2.0 Windows Application project with some custom UserControls; it worked fine.
So I decided to order my files in subfolders, to make my project a little bit cleaner.
After that, Visual Studio 2010 designer stopped loading my forms, and ToolBox won't show my controls anymore.
I freaked out, moving back source files in project root, resetting ToolBox, but nothing seemed to work.
After that, I remembered I used ReSharper "Remove Unused References", so I tried to put back unused reference, in particular System.Data: problem solved! :O
I can't say you why, but this worked for me.
Hope my experience can help someone else. :)
Bye,
Nando
I created an empty constructor for my custom implementation of UltraGridBagLayoutPanel. Although david.healed is right it isn't necessary, it is quite useful to put a breakpoint in to check that when the form initialises it is using your class to implement your custom control.
It would have been a lot easier to edit the designer file, but I tried it and changed both the field type for the control and also changed the assignment of the field to a new instance of my custom control.
private Infragistics.Win.Misc.UltraGridBagLayoutPanel ultraGridBagLayoutPanel1;
this.ultraGridBagLayoutPanel1 = new Infragistics.Win.Misc.UltraGridBagLayoutPanel();
to
private Athia.Reports.ultraGridBagLayoutPanel1 ultraGridBagLayoutPanel1;
this.ultraGridBagLayoutPanel1 = new Athia.Reports.ultraGridBagLayoutPanel1();
Doing this destroys Visual Studio every time, and to fix it requires using a text editor to put it back again. Therefore unless anyone can describe what is wrong with my implementation of this approach, perhaps calling the class the same as the control name isn't a great idea, I think the only safe and reliable way to achieve this is as Calanus describes in steps 1 to 5 or as an small deviation from that as Rob Windsor rightly points out restarting VS will bring the control into the Toolbox automatically. Unfortunately for me I then have to change all of the child controls over from the original class to my customised class :-(.
Within the same Solution this should work automatically. However, I have found that if the Target Framework aren't matching the Toolbox does not populate. ( I'm assuming really Reference needs to be of version same or lower than target of Reference. ) ( I did get a warning about non-matching Frameworks )
By making these the same Target Framework, Recompile, Restart VS. the control populated correctly. ( I also added the ToolboxItem(true) Attribute)