How to assign dataGrid to other dataGrid in Flex. a = b doesn't work

in Flex I have something like that:

  var dg:DataGrid = new DataGrid();    
  if (something) dg = dg1 else if (something_2) dg = dg2;
  dg.dataProvider.getItemAt(3).id;    

and dg is ALWAYS pointing at DataGrid (even if dg1 has name DataGrid_test and dg2 = DataGrid_test2) and finally action is made on my first DataGrid (DataGrid_test). Why? How can I pass dg1 or dg2 to dg?

Here is pasted almost full code of this part of application. I edited it to make that more clear.

    var dg:DataGrid = null; 
    if ( currentState == "state1" ) { //if this condition is true then app. go into if and
        dg = dataGrid_first; // make dg = DataGrid (1)
        test.text = "inco";  // shows "inco" in "test" label
    } else if ( currentState == "state2" ) { // if this is true then app. go..
        dg = dataGrid_second; //here and set dg as DataGrid (exactly!) (2)
        test.text = "outgo"; // and change test label into blank text (earlier text disapears)
    }
    search(dg);

It is modified with advice of '@splash' Still not working.

EDIT: I made this sceond edit to answer for all You who are helping me with that :) I think that it will be the best way. In codeblock above I added comments. (please read now comments and after that come back here :) ) Now I will explain exactly what happens. I debug it many times and here are results: dg is pointing at DataGrid (as component in flex, not as my dataGrid_first), I needed to extend DataGrid so now it is ColorColumn component (I don't know if I called it properly), not DataGrid. And dg is pointing at ColorColumn not at dataGrid_first or dataGrid_second. I even tried today the same thing what suggest @splash:

if ( currentState == "state1" ) { 
    test.text = "inco"; 
    search(dataGrid_first); 
} else if ( currentState == "state2" ) {
    test.text = "outgo";
    search(dataGrid_second);
}

and search still points at ColorColumn :/ My problem is really easy- I just want to pass to search different dataGrid on each state. If You have o开发者_开发问答ther ideas how I can do that in right way then I will pleased to hear about it. :) But still I don't understand why it doesn't work. My search function uses algorhitm Boyer-Moor for searching through dataGrid.dataProvider for some text. If it find something then it is pushed into new array and after passing whole dataProvider I colorize rows with searched word.

---

If dg is never pointing to dg1 and dg2 then your (something) expressions may be evaluate to false. Check the value of your if-conditions - this should be easy to debug.

This should work:

var dg:DataGrid = null;    
if (something) 
    dg = dg1;
else if (something_2) 
    dg = dg2;
if (dg)
{
    // do something with dg
}

[Update]

I still can't see why your code isn't working, but you could simplify it like this:

if ( currentState == "state1" ) { 
    test.text = "inco"; 
    search(dataGrid_first); 
} else if ( currentState == "state2" ) {
    test.text = "outgo";
    search(dataGrid_second);
}

---

I'd propose to write this - since I guess either dg1 or dg2 should be assigned:

if (something) {

    dg = dg1;

} else {

    dg = dg2;

}

There may be cases, where if () {} else () {} neither executes the first or the second conditional block.

Finally a small hint, which structurally eliminates unwanted assignments in if conditions: Always write the literal left of the comparison operation: if ( "state1" == currentState ). If you accidentally typed = instead of ==, the flex compiler emits an error. The other notation silently assigns a value.

Additionally: Did you single-stepped through your code and watched the variables dg1, dg2 and dg? If not, set a breakpoint a few line before the if-statement and run the code step by step from there on. What do you see?

Here's a another tip: Use assertions to check for inconistencies:

package my.company.utilities {

  public function assert(expression:Boolean):void {

      // probably conditionally compile this statement
      if (!expression) {
          throw new Error("Assertion failed!");
      }

  } // assert

}

Use it e.g. at the beginning of a method like this:

public function doTransaction( fromAccount:int, toAccount:int ) {

  assert( 0 < fromAccount );
  assert( 0 < toAccount );

}

A typically good use of assert is to check variables regarding their range. As of the above example, fromAccount and toAccount should always be positive. Due to a bug, bad values might get passed to doTransaction(). In this case, the assertion fires an error.