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Delphi 7 :: Have a WideString in Record

Posted on 2006-11-14
9
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Last Modified: 2010-05-18
Dear Experts,

I am using TTreeViewEx component which automates the process
of saving the TreeView's: Items, Images, Node.Data etc properties.

For this to work I need to declare a pointer to a Record containing all fields I want to store
in Node.Data.
The problem is that I need to be able to store fields of WideString type?
I realize can only do the following:

MyRecord = Record;
 UserName :String[255]   //Actually I need it to be of type: WideString
 UserSurname :String[255]
end;

Is store a solution to this?


Thanks!
0
Comment
Question by:Marius0188
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9 Comments
 
LVL 19

Expert Comment

by:MerijnB
ID: 17941017
you can use array of widechar:

MyRecord = record
 UserName: array[1..255] of WideChar;
 UserSurname: array[1.255] of WideChar;
end;
0
 

Author Comment

by:Marius0188
ID: 17941152
How do I type cast it to WideString then?

For example:

var
  WideChar :Array[1..255] of WideChar;
  WideString :WideString;
begin
   WideString := WideChar; //This would not compile
end;


0
 
LVL 19

Expert Comment

by:MerijnB
ID: 17941323
I think your piece of code doesn't compile because you have named your WideString variable 'WideString'.
Try this:

var
  WideChar :Array[1..255] of WideChar;
  WideStr :WideString;
begin
   WideStr := WideChar;
end;
0
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Author Comment

by:Marius0188
ID: 17941346
And also the other way around.
For Example:

WideChar := WhideStr


Thanks!
0
 

Author Comment

by:Marius0188
ID: 17941422
Nope it was not the reason.
I just typed the example here in experts-exchange.
Bad example sorry.

I get the compiler error messages:
"Incompatibles types: 'Array' and 'WideString' "
0
 

Author Comment

by:Marius0188
ID: 17941435
Ok sorry I am wrong.

The problem is WideString to  Array of WideChar.

Example:

WCharArray := WideStr
0
 
LVL 19

Expert Comment

by:MerijnB
ID: 17941623
I think this is easiest:

var WideArray: array [1..255] of widechar;
    WideStr: WideString;
begin
 WideStr := 'teststring';

 ZeroMemory(@WideArray[1], SizeOf(WideArray));
 CopyMemory(@WideArray[1], @WideStr[1], Length(WideStr) * SizeOf(WideChar));
end;
0
 

Author Comment

by:Marius0188
ID: 17941719
I get an EAccessViolation error when calling "CopyMemory....".
Something not working.

Let me explain what I am doing.

I have declared the following
------------------------------------------
Type
  PNodeData = ^TNodeData;
  TNodeData = Record;
     Url :Array[1..255] of WideChar;
end;
-----------------------------------------

Now when inserting a new TTreeNode in TTreeView I do the following:
----------------------------------------------------------------------------------
var
  Node :TTreeNode;
  NodeData :PNodeData;
  wsURL :WideString;
begin
  wsUrl := 'qwr34234234234234234234234234234234234324234234asdasd'; //For example purposes only
  GetMem(NodeData, SizeOf(TNodeData));
  NodeData^.Url := wsUrl;    //Problem here. Need to convert WideString to Array of WideChar or something.
                                        //And you code gives AccessViolation.
end;

----------------------------------------------------------------------------------
0
 
LVL 19

Accepted Solution

by:
MerijnB earned 500 total points
ID: 17941863
this works fine here ... ?

var
  wsURL :WideString;
  NodeData: PNodeData;
begin
  wsUrl := 'qwr34234234234234234234234234234234234324234234asdasd'; //For example purposes only
  GetMem(NodeData, SizeOf(TNodeData));

  ZeroMemory(@NodeData^.Url[1], SizeOf(NodeData^.Url));
  CopyMemory(@NodeData^.Url[1], @wsUrl[1], Length(wsUrl) * SizeOf(WideChar));
end;
0

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