Using Registry in Delphi

On 12.07.09, In Software, by ocitamala

Registry is a very vital part in the Windows. Because of its importance, a lot of viruses and hacking programs that use the registry as part of his illegal operations. In the present article, I’ll take playing around with the registry for a moment.

We start by declaring the Registry unit in the Uses, looks like:

Uses Registry;

It’s simple, isn’t it?. Go on. The registry data type can be:

Binary
String
DWord
Boolean

With different data types, then writing to the registry will use a different function. The following description will explain how to write each data type before.

A. Writing Binary Data

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    i : integer;
    DataKey : array of byte;
    info : TRegDataInfo;

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begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_CURRENT_USER;
…………………………………………………………..
Open registry
Example:
reg.OpenKey(’Control PanelAppearanceSchemes’,true);

OpenKey command takes two parameters. The first parameter is a subkey of the registry, while the second parameter declares whether allowed to make a key if the key is not found.
Write registry
Example:
DataKey[0] := $10;
reg.WriteBinaryData(’Aubergine’,pointer(DataKey)^, info.DataSize);
Close registry for saving all data that is wrote
reg.CloseKey;
Destroy object from memory
FreeAndNil(reg);

B. Read Binary Data

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    i : integer;
    DataKey : string;
begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_CURRENT_USER;
…………………………………………………………..
Open registry
Example:
reg.OpenKey(’Control PanelAppearanceSchemes’,true);
Read registry
Example:
reg.ReadBinaryData(’TempatData’, DataKey, sizeof(DataKey));
ShowMessage(DataKey);
Close registry. Without it, data is not saved
reg.CloseKey;
Releasing memory from object
FreeAndNil(reg);

C. Writing String Data

Below, I give example for writing autostart your program when windows

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    i : integer;
    DataKey : string;
begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_LOCAL_MACHINE;
…………………………………………………………..
Open registry
Example:
reg.OpenKey(’SoftwareMicrosoftWindowsCurrentVersionRun’,true);
Write this
Example:
reg.WriteString(’MyProgram’,'C:MyFolderProgramMyProgram.exe’);
Close registry object
reg.CloseKey;
Destroy object
FreeAndNil(reg);

D. Read String Data

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    i : integer;
    DataKey, IsiReg : string;
begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_LOCAL_MACHINE;
………………………………………………………………..
Open registry
Example:
reg.OpenKey(’SoftwareMicrosoftWindowsCurrentVersionRun’,true);
Read registry:
Example:
IsiReg := reg.ReadString(’MyProgram’);
ShowMessage(IsiReg);
Close registry
reg.CloseKey;
Erase object from memory
FreeAndNil(reg);

E. Writing DWord Data

The explanation below is about the writing of data type DWORD in the registry by taking samples in order to disable registry.

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    i : integer;
    DataKey, IsiReg : string;
begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_CURRENT_USER;
………………………………………………………………..
Open registry
Example:
reg.OpenKey(’SoftwareMicrosoftWindowsCurrentVersionPoliciesSystem’,true);
Write registry
Example:
reg.WriteInteger(’DisableRegistryTools’,00000001);
Close registry
reg.CloseKey;
Destroy object
FreeAndNil(reg);

F. Read DWord Data

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    i : word;
    DataKey : integer;
begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_CURRENT_USER;
…………………………………………………………
Open registry
Example:
reg.OpenKey(’SoftwareMicrosoftWindowsCurrentVersionPoliciesSystem’,true);
Read registry
Example:
i := reg.ReadInteger(’DisableRegistryTools’);
ShowMessage(IntTostr(i));
For saving data, we have to close registry
reg.CloseKey;
Always destroy object after using it
FreeAndNil(reg);

G. Write Boolean Data

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    i : word;
    DataKey : integer;
begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_CURRENT_USER;
…………………………………………………………
Open registry
Example:
reg.OpenKey(’SubKey’,true);
Read registry
Example:
reg.WriteBool(’DisableRegistryTools’);
For saving data, we have to close registry
reg.CloseKey;
Always destroy object after using it
FreeAndNil(reg);

H. Read Boolean Data

Instantiate the class of type Registry.
instantiating class must be preceded by declaring a variable as TRegistry. In the example below, the variable is the reg:
var
    reg : TRegistry;
    YesNo : Boolean;
    DataKey : integer;
begin
    reg := TRegistry.Create;
    reg.RootKey := HKEY_CURRENT_USER;
…………………………………………………………
Open registry
Example:
reg.OpenKey(’SubKey’,true);
Read registry
Example:
YesNo := reg.ReadBool(’DisableRegistryTools’);

if YesNo then
ShowMessage(’YES’)
else
ShowMessage(’NO’);
For saving data, we have to close registry
reg.CloseKey;
Always destroy object after using it
FreeAndNil(reg);