I am trying to add a web browser to an existing C# application, but, having not used C# in about 6 years, I am quite unfamiliar with how it works.
I am trying to add the browser to a partial class (again, something I am not familiar with) using the following code:
public partial class WebBrowser : WebBrowserBase{
public WebBrowser(){
...
}
...
}
However, I am getting a compile error on the constructor that says:
'WebBrowserBase' does not contain a constructor that takes 0 arguments
I Google'd this, and came across the following question on SO: C# Error: Parent does not contain a constructor that takes 0 arguments. I tried doing what was suggested in the answer to this, and changed my code to:
public partial class WebBrowser : WebBrowserBase{
public WebBrowser(int i) : base(i){
...
}
...
}
However, I then get a compile error that says:
'WebBrowserBase' does not contain a constructor that takes 1 arguments
So I'm guessing that this issue isn't to do with the number of arguments in the constructor... Can anyone explain what I'm doing wrong here?
If you have a look at WebBrowserBase Class it states that:
"This API supports the product infrastructure and is not intended to be used directly from your code."
And it seems that it doesn't have any public constructor - so you can't inherit from it. But if you don't want to create your own WebBrowser control (alter some of it's functionality), you should just use the default System.Windows.Forms.WebBrowser in a XAML View:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Width="525"
Height="350">
<WebBrowser HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
</Window>
In Inheritance,
If Derived class contains its own constructor which not defined in Base class then this error Occurs
For Example:
class FirstClass
{
public FirstClass(string s) { Console.WriteLine(s); }
}
class SecondClass : FirstClass
{
public SecondClass()
{
Console.WriteLine("second class");
}
}
Output: Error:-'myconsole.FirstClass' does not contain a constructor that takes 0 arguments
To Run without Error:
class FirstClass
{
public FirstClass()
{
Console.WriteLine("second class");
}
public FirstClass(string s) { Console.WriteLine(s); }
}
class SecondClass : FirstClass
{
public SecondClass()
{
Console.WriteLine("second class");
}
}
Related
I have declared a base dialog window class that types the datacontext to ensure that the attached viewmodel has the appropriate return type. When I try to use it though I get a generic arguments error:
GenericArguments[1],
'Mocks.MidSoft_Hospitality_ViewModels_Dialogs_ReceiveItemViewModel_32_569724456',
on
'Mocks.MidSoft_Hospitality_Views_Dialogs_BaseDialogWindow`2_32_569724456[TResult,TViewModel]'
violates the constraint of type 'TViewModel'.
I can't see why this would be happening
The base dialog window declaration:
public class BaseDialogWindow<TResult, TViewModel> : DialogWindowBase<TResult> where TViewModel: ViewModels.Dialogs.DialogBaseViewModel<TResult>
{
public BaseDialogWindow() : base()
{
}
new public TViewModel DataContext
{
get => this.GetValue(DataContextProperty) as TViewModel;
set => this.SetValue(DataContextProperty, value);
}
}
DialogWindowBase:
public class DialogWindowBase<TResult> : Window, IDialog<TResult>
{
public DialogWindowBase()
{
//Formatting code here
}
public Result Result { get; set; } = Result.None;
public TResult ReturnData { get; set; }
}
The viewModel:
public class ReceiveItemViewModel : ViewModels.Dialogs.DialogBaseViewModel<ReceiveItemResult>
{
//View Model Code here
}
and the xaml:
<local:BaseDialogWindow x:Class="MidSoft.Hospitality.Views.Dialogs.ReceiveItemDialog"
x:TypeArguments="local:ReceiveItemResult, vm:ReceiveItemViewModel"
xmlns:vm="clr-namespace:MidSoft.Hospitality.ViewModels.Dialogs"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MidSoft.Hospitality.Views.Dialogs"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance vm:ReceiveItemViewModel, IsDesignTimeCreatable=False}"
x:Name="ReceiveStockItemDialog"
Height="450" Width="800">
<Grid>
</Grid>
</local:BaseDialogWindow>
Code for the dialog:
public partial class ReceiveItemDialog
{
public ReceiveItemDialog()
{
InitializeComponent();
}
}
The error that I referenced above is the only compiler error that I am getting. I would appreciate any insight into this error.
Update: I have now noticed that the application is compiling and running without any exceptions being thrown but the error is still there and the xaml designer is showing it as invalid markup
IsDesignTimeCreatable=False will force the designer to ignore the specified DesignInstance type and create a substitute type using reflection. In this case the designer failed to recognize the generic type as it is a complex type rather than a primitive type and therefore failed to create a proper mock instance with a proper generic parameter TViewModel.
To solve this, you could set the IsDesignTimeCreatable property to True and implement a default constructor on ReceiveItemViewModel. If a default constructor is not possible, introduce a wrapper type just for the design time DesignInstance and spend it a a default constructor that initializes the base type ReceiveItemViewModel properly.
Hi I'm currently stuck with this weird behaviour of Visual Studio
I've got this Base Class here:
namespace IntelliListDemo.Controls
{
public class NodeControlBase : UserControl
{
public NodeControlBase(NotYetGenericOutputNode internalNode)
{
this._internalNode = internalNode;
}
public NodeControlBase() { }
}
}
And i have some controls deriving from it. An Example:
namespace IntelliListDemo.Controls
{
/// <summary>
/// Interaktionslogik für Source.xaml
/// </summary>
public partial class SourceControl : NodeControlBase//, ISourceControl, INodeControl
{
public SourceControl(IntelliListLibrary.Nodes.SourceNode internalNode) : base(internalNode)
{
InitializeComponent();
}
}
And the XAML:
<Controls:NodeControlBase x:Class="IntelliListDemo.Controls.SourceControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:Controls="clr-namespace:IntelliListDemo.Controls"
mc:Ignorable="d"
>
</Controls:NodeControlBase>
So I always get compiler Errors saying
The name "NodeControlBase" does not exist in Namespace
"clr-namespace:IntelliListDemo.Controls".
Found this old question when I had the same problem. Turned out I had a syntax error in my XAML code in another file that was preventing the build completing, and so the reference to the base class could not be resolved.
The way I tracked it down was commenting out the code related to the base UserControl class and making sure I had a clean compile - and being sure to check all the derived views when I re-introduced the new code!
I'm having trouble with naming my Window which is inherited from its Base Window,
when I try to give a name to my Window I get following error.
The type BaseWindow cannot have a Name attribute. Values types and types without a default constructor can be used as items within ResourceDictionary.
XAML :
<log:BaseWindow
x:Class="EtraabMessenger.MainWindow"
x:Name="main"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:log="clr-namespace:EtraabMessenger.MVVM.View.Controls"
xmlns:VMCore="clr-namespace:EtraabMessenger.MVVM.VMCore"
VMCore:WindowClosingBehavior.Closing="{Binding DoCloseMainWindowCommand}"
Height="464" Width="279">
</log:BaseWindow>
EDIT : Here is my BaseWindow class
public abstract class BaseWindow : Window, INotifyPropertyChanged
{
protected BaseWindow()
{
// Note (Important) : This message should register on all windows
// TODO : I'm planning to move this registeration to BaseWindow class
Messenger.Register<bool>(GeneralToken.ClientDisconnected, DisconnectFromServer);
}
protected abstract void DisconnectFromServer(bool isDisconnected);
protected abstract void RegisterTokens();
protected abstract void UnRegisterTokens();
....
....
....
}
Any advice will be helpful.
Your base window apparently, as the error states, needs a public default contructor (one without arguments), it also may not be abstract because an instance of it needs to be created.
I am having trouble calling base constructors in wpf windows:
public class TemplateWindow : Window //Template window class
{
public TemplateWindow (int no)
{
}
}
public partial class MainView : TemplateWindow
{
public MainView() : base(1) //error here
{
InitializeComponent();
}
}
It gives me an error at the indicated location as it apparently is trying to call the Window constructor with base instead. The MainView class is the code behind of a xaml window.
However, when I tested the problem like below, it works perfectly fine.
class A //Base Class
{
public A() { }
}
class B : A
{
public B(int no) { }
}
partial class C : B
{
public C() : base(1) { }
}
What am i doing wrong?
You have your MainView class defined in XAML, don't you? It probably goes something like this:
<Window x:Class="MyNamespace.MainView" ... >
...
</Window>
Note the big Window word right at the beginning. It tells the compiler that you want this XAML to generate a class named MyNamespace.MainView, and you want it to inherit from Window. So that's what the compiler does: it happily generates your class and makes it inherit from Window. Right-click the InitializeComponent word and choose "Go to Definition". This will take you to the autogenerated file, and you'll be able to see the class.
Now, if you want MainView to inherit from TemplateWindow, you just have to say so in your XAML:
<my:TemplateWindow
xmlns:my="MyNamespace"
x:Class="MyNamespace.MainView" ... >
...
</my:TemplateWindow>
But that will give you another problem: now, all of a sudden, you can't use the visual designer.
That would be because the designer cannot create an instance of your TemplateWindow class for editing. Why? Well, because TemplateWindow doesn't have a default constructor, of course!
So for this kind of thing to work, you'll just have to define two constructors in TemplateWindow - one default, and one accepting an int.
Good luck.
Here is your answer
http://geekswithblogs.net/lbugnion/archive/2007/03/02/107747.aspx
The following WPF UserControl called DataTypeWholeNumber which works.
Now I want to make a UserControl called DataTypeDateTime and DataTypeEmail, etc.
Many of the Dependency Properties will be shared by all these controls and therefore I want to put their common methods into a BaseDataType and have each of these UserControls inherit from this base type.
However, when I do that, I get the error: Partial Declaration may not have different base classes.
So how can I implement inheritance with UserControls so shared functionality is all in the base class?
using System.Windows;
using System.Windows.Controls;
namespace TestDependencyProperty827.DataTypes
{
public partial class DataTypeWholeNumber : BaseDataType
{
public DataTypeWholeNumber()
{
InitializeComponent();
DataContext = this;
//defaults
TheWidth = 200;
}
public string TheLabel
{
get
{
return (string)GetValue(TheLabelProperty);
}
set
{
SetValue(TheLabelProperty, value);
}
}
public static readonly DependencyProperty TheLabelProperty =
DependencyProperty.Register("TheLabel", typeof(string), typeof(BaseDataType),
new FrameworkPropertyMetadata());
public string TheContent
{
get
{
return (string)GetValue(TheContentProperty);
}
set
{
SetValue(TheContentProperty, value);
}
}
public static readonly DependencyProperty TheContentProperty =
DependencyProperty.Register("TheContent", typeof(string), typeof(BaseDataType),
new FrameworkPropertyMetadata());
public int TheWidth
{
get
{
return (int)GetValue(TheWidthProperty);
}
set
{
SetValue(TheWidthProperty, value);
}
}
public static readonly DependencyProperty TheWidthProperty =
DependencyProperty.Register("TheWidth", typeof(int), typeof(DataTypeWholeNumber),
new FrameworkPropertyMetadata());
}
}
Ensure that you have changed the first tag in the xaml to also inherit from your new basetype
So
<UserControl x:Class="TestDependencyProperty827.DataTypes.DataTypeWholeNumber"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:s="clr-namespace:System;assembly=mscorlib"
>
becomes
<myTypes:BaseDataType x:Class="TestDependencyProperty827.DataTypes.DataTypeWholeNumber"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:s="clr-namespace:System;assembly=mscorlib"
xmlns:myTypes="clr-namespace:TestDependencyProperty827.DataTypes"
>
So, to summarise the complete answer including the extra details from the comments below:
The base class should not include a xaml file. Define it in a single (non-partial) cs file and define it to inherit directly from Usercontrol.
Ensure that the subclass inherits from the base class both in the cs code-behind file and in the first tag of the xaml (as shown above).
public partial class MooringConfigurator : MooringLineConfigurator
{
public MooringConfigurator()
{
InitializeComponent();
}
}
<dst:MooringLineConfigurator x:Class="Wave.Dashboards.Instruments.ConfiguratorViews.DST.MooringConfigurator"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:dst="clr-namespace:Wave.Dashboards.Instruments.ConfiguratorViews.DST"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="400">
<Grid x:Name="LayoutRoot" Background="White">
</Grid>
</dst:MooringLineConfigurator>
I found the answer in this article: http://www.paulstovell.com/xmlnsdefinition
Basically what is says is that you should define an XML namespace in the AssemlyInfo.cs file, which can the be used in the XAML. It worked for me, however I placed the base user control class in a separate DLL...
There is partial class definition created by designer, you can open it easy way via InitializeComponent() method definition.
Then just change partial class iheritence from UserControl to BaseDataType (or any you specified in class definition).
After that you will have warning that InitializeComponent() method is hidden in child class.
Therefore you can make a CustomControl as base clas instead of UserControl to avoid partial definition in base class (as described in one comment).
I ran into the same issue but needed to have the control inherit from an abstract class, which is not supported by the designer. What solved my problem is making the usercontrol inherit from both a standard class (that inherits UserControl) and an interface. This way the designer is working.
//the xaml
<local:EcranFiche x:Class="VLEva.SIFEval.Ecrans.UC_BatimentAgricole"
xmlns:local="clr-namespace:VLEva.SIFEval.Ecrans"
...>
...
</local:EcranFiche>
// the usercontrol code behind
public partial class UC_BatimentAgricole : EcranFiche, IEcranFiche
{
...
}
// the interface
public interface IEcranFiche
{
...
}
// base class containing common implemented methods
public class EcranFiche : UserControl
{
... (ex: common interface implementation)
}