Re: Help for hDC and textcontrol.com's ActiveX Control

From: Fred Taylor (ftaylor_at_mvps.org!REMOVE)
Date: 02/16/05 

Date: Wed, 16 Feb 2005 08:08:08 -0700

Fox Controls are not "real" Windows controls, in that they don't have a
Windows handle or anything like that. You're picturebox control would need
to be an ActiveX control and if it is, you may need to reference the
property as thisform.picture1.object.hDC. 

-- 
Fred
Microsoft Visual FoxPro MVP
"Tom Clark" <tjclark@pc-enable.com> wrote in message 
news:1116jlasqavki8d@corp.supernews.com...
> Hi All,
>
> I posted this in the wrong thread.  Sorry for the repost.
>
> Eric den Doop suggested I take a look at TextControl.com's ActiveX control
> for print previewing MS-Word or RTF documents.  I downloaded the trial
> version and I am having a problem with the code.
>
> According to the Help File:
>
> "Text Control's PrintPage method can not only be used with printers, but
> also with any control that has a hDC property. For instance. a PictureBox
> can be used as a print preview window. This is done by simply assigning 
> its
> hDC Property to Text Control's PrintDevice Property. When calling 
> PrintPage,
> Text Control will print to the Picture Box instead of to the printer.
>
> This code snippet will print page 1 to a picture box named Picture1. You 
> can
> use the PrintZoom Property to scale down the printout if the picture box 
> is
> smaller than a full printer page:
>
> TXTextControl1.PrintDevice = Picture1.hDC
> TXTextControl1.PrintZoom = 25 ' scale down to 25%
> TXTextControl1.PrintPage 1"
>
> The MDIDemo sample program contains a sophisticated print preview form 
> that
> works like this. Its source code is contained in the Samples\VB6\MDI
> folder."
>
> Well I have adapted that example as best I could with the following code:
>
> cDoc = "c:\pcenable\rtf\jdis2.doc"
> thisform.oTxt.Load(cDoc,,9,)
> thisform.oTxt.PrintDevice = Picture1.hDC
> thisform.oTxt.PrintZoom = 25 && scale down to 25%
> thisform.oTxt.PrintPage(1)
>
> The code generates the following run time error "Alias 'Picture1' is not
> found."
>
> I have named the image control to "Picture1" but I realize that my problem
> is that I have no idea what hDC is!  Any help would be appreciated.
>
> TIA,
> Tom Clark
>
> Bernhard Sander replied:
>
> "If your "Picture1" is on the same form then the above line should read:
>  thisform.oTxt.PrintDevice = THISFORM.Picture1.hDC"
>
> Which I tried and the new error is "Property hDC not found."
>
> MSDN says the following in regards to Visual BASIC:
>
> Syntax
> object.hDC
> The object placeholder represents an object expression that evaluates to 
> an object in the Applies To list.
> Remarks
> This property is a Windows operating environment device context handle. 
> The Windows operating environment manages the system display by assigning 
> a device context for the Printer object and for each form and PictureBox 
> control in your application. You can use the hDC property to refer to the 
> handle for an object's device context. This provides a value to pass to 
> Windows API calls.
> With a CommonDialog control, this property returns a device context for 
> the printer selected in the Print dialog box when the cdlReturnDC flag is 
> set or an information context when the cdlReturnIC flag is set.
> Note   The value of the hDC property can change while a program is 
> running, so don't store the value in a variable; instead, use the hDC 
> property each time you need it.
> The AutoRedraw property can cause the hDC property setting to change. If 
> AutoRedraw is set to True for a form or PictureBox container, hDC acts as 
> a handle to the device context of the persistent graphic (equivalent to 
> the Image property). When AutoRedraw is False, hDC is the actual hDC value 
> of the Form window or the PictureBox container. The hDC property setting 
> may change while the program is running regardless of the AutoRedraw 
> setting.
> If the HasDC property is set to False, a new device context will be 
> created by the system and the value of the hDC property will change each 
> time it is called.
>

Relevant Pages

  • Re: Help for hDC and textcontrol.coms ActiveX Control
    ... Microsoft Picture Clip Control v6 and the new error in both ... You're picturebox control would ... >> hDC Property to Text Control's PrintDevice Property. ... >> a device context for the Printer object and for each form and PictureBox ...
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