The CheckDlgButton function changes the check state of a button control.
BOOL CheckDlgButton(
| HWND hDlg, | // handle to dialog box | 
| int nIDButton, | // button-control identifier | 
| UINT uCheck | // check state | 
| ); | 
| Value | Meaning | 
| BST_CHECKED | Sets the button state to checked. | 
| BST_INDETERMINATE | Sets the button state to grayed, indicating an indeterminate state. Use this value only if the button has the BS_3STATE or BS_AUTO3STATE style. | 
| BST_UNCHECKED | Sets the button state to unchecked | 
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
The CheckDlgButton function sends a BM_SETCHECK message to the specified button control in the specified dialog box.