C# typecast basic query

I am new to C#

I have a struct like

struct Package
{
Public int[] intvalues;
Public char[] charva开发者_运维知识库lues;
Public string strvalue;
}

Now I have a string

string strquery;

I want to take the value of intvalues of the Package whose name is strquery.

As far as I tried, this didnt work

(Package)strquery.strvalue

Please help

Well, you can't do anything like that. Because for a string isn't defined any explicit casting operator such as your struct Package.

Also, the strquery.strvalue is completely wrong, as the string doesn't have such a field.

You can try what Phaedrus said.

From what you've said until now I think you are doing something like this:

List<Package> listOfPackages =new List<Package>();
// You fill up here the list
foreach (Package pkg in listOfPackages)
{
   if (pkg.strvalue == strquery)
   {
       Console.WriteLine("found a package with items:");
       // write the pkg.intvalues
       for(int i=0;i<pkg.intvalues.Length;i++)
           Console.Write(pkg.intvalues[i].ToString());
       Console.WriteLine(" ");
    }
}

First, please clarify your code since it doesn't make any sense.

Second, ask yourself why are you using a struct? are you certain you need a struct? and not a class? look at other questions on StackOverflow that get into that topic.

Third

(Package)strquery.strvalue

Is not valid code. strquery is a string and cannot be casted into Package struct. These are not objects related to each other at any level. (except that they both derive from object class)

Fourth if I were to assume you have a collection of Package based on your "question"

I want to take the value of intvalues of the Package whose name is strquery.

You want something like this

int[] foundValues;
foreach(Package pack in packageCollection)
{
   if( pack.strvalue == strquery)
      {
         foundValues = pack.intvalues;
         break;
      }
}

You cant cast a string type to a package type. To get the value of the strvalue you need to create a Package struct object first.

Package package = new Package();
...
string value = package.strvalue;

If I understand the question it appears you are need a dictionary of sorts where and int value would be associated with a key. If you changed your struct to look like this:

class Package // I would recommend using a class
{
    Public Dictionary<string, int> intValues;
}

then you could "query" the int value that had the correct key like this...

var strQuery = "intA";
var pakage = new Package()
pakage.intValues = new Dictionary<string, int>()
{
   new KeyValuePair<string, int>("intA", 0),
   new KeyValuePair<string, int>("intB", 0),
   new KeyValuePiar<string, int>("intC", 9),
}

var result = pakage.inValues[strQuery];

But this really is just enumerating a collection to find a value based on a key and your question could really use some clarification. Why don't you post what your trying to do without trying to suggest what code to use...

It appears as though you might be trying to parse a String using your Package struct. If so then you might try something like this by converting your structure to encapsulate and manipulate a string.

struct Package {
    public Package(string str) { //constructor
        strvalue = str;
    }
    public int[] Get_intvalues() { // method version
        // Convert stvalue into int array and return it.
        return new[] {1,2,3}; //example
    }
    public char[] Get_charvalues() { // method version
        return strvalue.ToCharArray();
    }
    public string strvalue; // string to work upon
}

This would allow you to use your Package struct with a string like so:

string str = "this is a test";
Package pkg = new Package(str);
pkg.Get_charvalues();
pkg.Get_intvalues(); //etc.