I'm creating static partial class like this.
If I put them in the same file there is no problem, but when I move one class to another file in the same project, this method private_method_from_a() does not exist anymore.
Is this by design? Do I miss something here?
//File A
public static partial class PartialClass
{
private static void private_method_from_a()
{
//Do something
}
}
//File B
public static partial class PartialClass
{
public static void public_method_b()
{
private_method_from_a();
}
}
Most likely the two files are in different namespaces, as #MickyD suggested in a comment. The reason for this problem is you're then making 2 different classes entirely. Chances are, one of them is in the namespace of your project, while the other is in the global namespace - that is, you didn't specify a namespace for it at all. Here's how the compiler sees them (suppose your project is called "MyProject", and has that name as the top-level namespace):
partial class global::MyProject.PartialClass
and
partial class global::PartialClass
Well, that's two distinct types, with different fully qualified names, both partial.
Make sure they're are both in the same namespace for the C# compiler to treat them as the same type.
Related
It was taught to me that any alterations to an object on a form (change the text, make visible/invisible or change the color and so on) should be done in the corresponding form class.
But due to the large amount of such alterations done inside the project, the file has became large and hard to search through. I've read online that a Partial Class could help, but there was no explanation on how to implement this. As an easy example, I have the following 2 files:
Form_Main.cs
namespace Test
{
partial class Form_Main : Form
{
public Form_Main()
{
InitializeComponent();
}
}
}
AND Form_Main.Dataloader.cs
namespace Test
{
partial class Form_Main : DataLoader
{
public void SetText()
{
TextBox_StudentSurname.Text = "1";
}
}
}
How can I make this work? Because if I do this I get several errors in the designer.
Your main problem is the first error printed: You cannot declare different base classes in different partial implementations. I don't know which of the two base classes is the right one (the one you previously used), but as always, a class cannot have two base classes. It is legal to specify the base class only in one of the parts, but if it is specified multiple times, it must be the same.
It would be great if this would work. Am I trying to implement my idea in the wrong way?
I would like to use partial method, to be able to extend existing code, and simply plug in/out implementation of methods.
Basically exactly what the reference is stating:
Partial methods enable class designers to provide method hooks,
similar to event handlers, that developers may decide to implement or
not. If the developer does not supply an implementation, the compiler
removes the signature at compile time.
My first try of using this is the following:
DefinitionsBase.cs:
namespace ABC {
public partial class Definitions {
// No implementation
static partial void TestImplementaion();
}
}
DefinitionsExt.cs:
namespace ABC {
public partial class Definitions {
static partial void TestImplementaion(){
// Implementation is here
}
}
}
Program.cs:
namespace ABC {
class Program {
static void Main(string[] args) {
Definitions.TestImplementaion();
}
}
}
It's same namespace, but as reference states partial methods are implicitly private. It doesn't accept access modifiers and I cannot call it from my class. Is there a way to use it as I intend to?
Thanks!
You could use a public method that calls the private method, but I am not sure if this is what you want. This just makes your code work.
Partial methods are by definition private so as during compilation time, in case the method was not implemented, the compiler does not need to go through all of the code, find all possible references to the method, and remove them.
This is a design choice since partial methods do not necessarily need to be implemented, the compiler only looks in the partial class implementation and not throughout all of the code.
If you implement a public method that calls the partial method and the partial method was not implemented, the compiler will still only look in the partial class files and code, even though you have access to that partial method from anywhere in your code.
This was a general question asked by a colleague of mine....
Is it possible to "outsource" code, and then call it in the main class (e.g. Form1.cs)?
This originates from the fact that he wants to organize his amount of code better than with regions, in the main class.
My first thought was - of course it is!
Use static Extentions, reference it to the main class, and call it through this.Method().
But he meant something like the "include" pattern in PHP....
Is that even possible?
he wants to organize his amount of code better than with regions, in the main class.
You can use partial classes to split the implementation of a single class into multiple (and perhaps more manageable) source files.
In File1.cs:
public partial class MyClass {
public void F() { ... }
}
In File2.cs:
public partial class MyClass {
public void G() { ... }
}
MyClass now has two methods, F and G.
You can externalize using partial classes or decouple it using c# assembly (dll).
I'm trying to group together MANY helper classes into a common parent class for ease of use. For example, in my applications I want to do
Tools.StringTool.foo(..)
Tools.NumberTool.bar(..)
Tools.NetworkTool.something(...)
The idea here is to organize all the tools under a common Tools class so that intellisense can bring them all up when I type "Tools.".
Defining all the tools under a parent static partial class Tools works fine but not for Tools in a different assembly.
I tried to emulate static partial classes across assemblies by replacing the parent Tools class with a namespace X.Y.Tools, but for code written outside X.Y namespace, I need to fully qualify each tool before using it.
i.e. in app code
Tools.MyTool(..) // won't compile
X.Y.Tools.MyTool(...) // will compile but ugly
Any suggestions how I can solve this issue or alternative approaches for organizing the tools?
You can use extension methods in this case. All extension methods defined in classes within a namespace are made available when that namespace is imported.
This way you'd have static classes like MyUtilityNamespace.MyClassInAssembly1 and MyUtilityNamespace.MyClassInAssembly2 that all provide extension methods onto a single class instance, but this has ugliness associated with getting that class instance, like so:
// in central assembly
class Tool {
private static Tool _t = new Tool();
public static Tool T { get { return _t; } }
}
// in utility assembly 1
public static class MyExtensionClassInAssembly1 {
public static void SomeUtilityMethodX(this Tool tool, Object arg1, Object arg2) {
// do something
}
}
// in utility assembly 2
public static class MyExtensionClassInAssembly2 {
public static void SomeUtilityMethodY(this Tool tool) {
// do something
}
}
You'd use it like so:
Tool.T.SomeUtilityMethodX( Tool.T.SomeUtilityMethodY(), null );
it isn't pretty, but means you only need to import an namespace once, and the Tool.T is constant, there's no need to memorize StringTool or NetworkTool.
Another alternative is to use namespace or type aliasing, however this is laborious as you need to specify the using Tools = X.Y.Tools.MyTool; line on every source file you have.
Turns out the easiest way to do this is simply use namespaces
// in project 1
namespace Tools {
public static class NetworkTool {
}
}
// in project 2
namespace Tools {
public static class FileTool {
}
}
// in client code (references both projects)
Tools.NetworkTool.SomeMethod();
Tools.FileTool.SomeMethod()
I've created a program with some very big .cs files. So i tried to split one of them up by using partial classes. So i created a second file with same class name inside and same namespace.
I cut some functions from one file and pasted it in the second one. But when i want to run the program it says that the class already exists. But its a partial class it has to have the same name :S
At the first file (ChartWidget.cs) it starts with:
namespace UGS.Sidebar.ChartWidget
{
public partial class ChartWidget : UserControl
{
#region declarations
private int id = -1;
.....
At the second file (Debugging.cs) it starts with:
namespace UGS.Sidebar.ChartWidget
{
public partial class ChartWidget : UserControl
{
#region debugvars
Random _r = new Random();
#endregion
.....
those files are from an Usercontrol (as you can see) but i dont think that this is the problem?
Hope you guys can tell me why it doesnt work :(
And sorry for my bad english i really suck ... :)
Check you haven't appended the class name on to the end of a namespace. e.g. if you put your new class into a folder of the same name, it will automatically get suffixed on the namespace name
No need to inherit from UserControl in second class
Check if somewhere else the class is defined without the partial. Right click on the class name + Find All Reference could help.