We Keep Coding

How to create my own parameter method

I saw some code from a C# Console Application that can pass a string-valued parameter . My question is how can I create my own parametered method?
For example, the following code will pass the parameter value to {0} and print the string with value of Leonel.
Console.Write("{0}", "Leonel");
How can I make a method that can pass a parameter value to string format and return a parameterize string?
public string Combine(string format, params object[] args)
{
var parameterize = //("{0}", args) //I need something like this.
return parameterize;
}

I'm not totally clear on what you're asking, but would calling string.Format work?
string str = string.Format("The value is: {0}", val);
That should call the same underlying function as Console.Write does. It returns the string that would otherwise be printed to the Console. Given that, you probably don't even want your Combine method, as string.Format would take its place.

You can use the static method
string.Format(string str, params string[] formatters);
with your example:
public string Combine(string format, params object[] args)
{
var parameterize = string.Format(format, args);
return parameterize;
}

Extension Methods. Error No overload for method 'WriteTextToConsole' takes 1 arguments

I'm learning C# and C and this C# code is giving me an error I don't understand. I'm reading about extension methods and this code is giving the error: No overload for method 'WriteTextToConsole' takes 1 arguments. As you can see, it takes exactly 1 arguments? I created the variables c and count only to be able to construct the string object. So I could try the extension in the String class. Is it right understood that the way you create an extension method: is to precede the parameter with the "this" keyword and the parameter is of the type of class to be extended?
The code is here:
Console.WriteLine();
M.WriteTextToConsole("Hello, world. Programming in C# is fun");
char c = 'A';
int count = 14;
String str = new String(c, count);
str.WriteTextToConsole("This is a string");
The method is here:
static class M
{
public static void WriteTextToConsole(this string text)
{
Console.WriteLine(text);
}
}

you need to call it as str.WriteTextToConsole();. In this case str would be passed as a single argument to M.WriteTextToConsole() method

When you call the extension method on the string the "this string text" parameter refers to the string itself,for example if it where "this Bitmap b" it would be an extension method for the bitmap and assuming you had created a bitmap object named bit the call would be bit.WriteTextToConsole().If you want to had other parameters you need to add those to to the method declaration and to make so it is an option for the caller make it with the params keyword like so:
static class M
{
public static void WriteTextToConsole(this string text,params string[] str)
{
if (str.Length > 0)
{
//do something with extra string or strings
//you can make params Object[] but for this
//example i choose string[]
Console.WriteLine(text);
return;
}
Console.WriteLine(text);
}
}
Just remenber the this keyword must be the first parameter,refering to the type you are extending.
In the case of having optional strings i left the code with the duplicate console.WriteLine(text) you can rewrite it if you in both cases want the string displayed in the console(just remove the return and console writeline above it).

Extension error assignment, how to fix?

We suppose that for example i have a string, and i want to escape it, and to be well reading)
need a working extension what will solve this problem
i tried.
var t = "'";
t.Escape();// == "%27" (what i need), but it not assign result to var. t
t = t.Escape();//works, but ugly.
and the extension
public static string Escape(this string string_2)
{
if (string_2.HasValue())
string_2 = Uri.EscapeDataString(string_2);
return string_2;
}
how to fix this extension be working?

t = t.Escape(); is the usual idiom in .NET for changing a string. E.g. t = t.Replace("a", "b"); I'd recommend you use this. This is necessary because strings are immutable.
There are ways around it, but they are uglier IMO. For example, you could use a ref parameter (but not on an extension method):
public static string Escape (ref string string_2) { ... }
Util.Escape(ref t);
Or you could make your own String-like class that's mutable:
public class MutableString { /** include implicit conversions to/from string */ }
public static string Escape (this MutableString string_2) { ... }
MutableString t = "'";
t.Escape();
I'd caution you that if you use anything besides t = t.Escape();, and thus deviate from normal usage, you are likely to confuse anyone that reads the code in the future.

"Mutable string" in C# is spelled StringBuilder.
So you could do something like this:
public static void Escape(this StringBuilder text)
{
var s = text.ToString();
text.Clear();
text.Append(Uri.EscapeDataString(s));
}
But using it wouldn't really be that great:
StringBuilder test = new StringBuilder("'");
test.Escape();
Console.WriteLine(test);
The real answer is to use the "ugly" string reassignment
t = t.Escape();//works, but ugly.
You'll get used to it. :)

Way to get all method parameters in solution

Is there way in C# to get all parameters which were used with some extension method?
Example:
public static string GlueStrings(this string mystring, string otherString)
{
return mystring + otherstring;
}
In some method in Form1
string string1 = "Glued";
string string2 = string1.GlueStrings("Strings");
In some method in Form2
string string1 = "Foo";
string string2 = string1.GlueStrings("bar");
Is there a way I can create method which would list all parameters used with that method in whole solution, I am interested in parameter otherString from whole solution?
UPDATE:
This with strings is just an example, I need it to work with different types. Like in MVC Controller annonations where you can get all controllers where some annonation is used.

You could keep a static ConcurrentBag in your class and add each parameter to it at runtime.
(concurrent collection for thread safety http://msdn.microsoft.com/en-us/library/system.collections.concurrent.aspx)

Not the best way to do it when it comes to performance
but you can use MethodBase.GetParameters
Else
how about GlueStrings(this string mystring, params object[] others)
PS: I have not tried it or unit tested it
Update: Example on request by you
Suppose Class Glue have the method GlueStrings then:
ParameterInfo[] parameterInfos = typeof (Glue).GetMethod("GlueStrings").GetParameters();

How is String.Format method treated?

As is described at Microsoft Site ,String.Format arranges some String Variables into a single String and is another way how to concate string's in c#.
string.Format("Name = {0} Surname = {1}",name,surname);
My question is how does this work ?
Is this method a Special method ,and can i create a method similar to this one which accepts at every {n} only an Integer .
Or is this method interpreted in a different way by compiler ,if yes than how does the compiler accesses this method .
If it's possible i would like to see ,how does the compiler interpret this Method.
PS : How does it work ,when you can send as much parameters as you want to a method ?
[EDIT]
Does it mean ,that String.Format takes the first Parameter and filter's into with a Regex or Whatever tool (Split etc) to get where {Number} is and places there a String token from second params portion ?

Sending a variable number of parameters to a method is done like this:
public static string MyStringFormat(string formatString, params object [] args)
{
}
You can now pass as many parameters as you like to this:
MyStringFormat("{0}{1}",42,"Hello World")
MyStringFormat("{0}{1}{2}",42,"Hello World",999.9)
Within the method, these arguments are simply an array (of object in this case).
here are the docs on the params keyword.
As for writing you own method to accept numeric input like Format does, this would be one way (using regular expressions):
public static string MyStringFormat(string formatString, params object[] args)
{
var regex = new Regex("{([0-9]*)}");
return regex.Replace(formatString,m =>
{
int index = int.Parse(m.Groups[1].Value);
if(index<args.Length)
return args[index].ToString();
return String.Empty;
});
}
Live example: http://rextester.com/rundotnet?code=OMZC13551

It is a normal function.
It parses the string and calls ToString on the incoming parameters (if needed) in order to construct the new string.
The signature of the overload you have in your example is:
public static string Format(
string format,
params Object[] args
)
There is nothing to stop you from creating your own (though I would probably just delegate to the built in string.Format).

Use params: http://msdn.microsoft.com/en-us/library/w5zay9db.aspx

there is no magic there Cody, look at this method:
public static void UseParams(params int[] list)
{
for (int i = 0 ; i < list.Length; i++)
{
Console.WriteLine(list[i]);
}
Console.WriteLine();
}
you can call it passing as many int you like, it's the params parameter type :)
Edit:
params is very useful it allows us, for example, to pass to our logging wrapper all method's parameters values in a dynamic way without knowing how many of them each method has, the logger will then dump all those values one by one using Reflection to find out the parameter name as well.

The braces in the string are placeholders and a number within that denotes the index of argument it is to be replaced with.
Format is of type (string format, params object[] args) and it is the index in this object[] which is helpful.
(I think it internally uses the StringBuilder.AppendFormat) for substituting those values)

The signature of String.Format looks like this:
public static string Format (string format, params Object[] args)
Note the second parameter, marked with the params keyword. That one provides the functionality to add multiple parameters when calling the function. Inside the function you can access the parameters by index or iterating over args array:
public static string Format (string format, params Object[] args)
{
foreach (Object o in args)
Console.WriteLine(o);
}
Have a look at the C# Reference.