TMonitor combines the notion of a critical section (or a simple mutex) along with a condition variable. You can read about what a “monitor” is here: http://en.wikipedia.org/wiki/Monitor_%28synchronization%29 Any place you would use a critical section, you can use a monitor. Instead of declaring a TCriticalSection, you can simple create a TObject instance and then use … Read more
The following example uses the interposed class of the TComboBox component. The main difference from the original class is that the items are stored in the separate StoredItems property instead ofthe Items as usually (used because of simplicity). The StoredItems are being watched by the OnChange event and whenever you change them (for instance by … Read more
tl;dr; Use GDI+ SetWorldTransform With WinAPI’s SetWorldTransform you can transform the space of device context: rotate, shear, offset, and scale. This is done by setting the members of a transform matrix of type XFORM. Fill its members according the documentation. procedure RotateBitmap(Bmp: TBitmap; Rads: Single; AdjustSize: Boolean; BkColor: TColor = clNone); var C: Single; S: … Read more
Marco Cantu is a big believer in InstantObjects: Home Others include DObject: http://www.macrobject.com/en/dobject/ and tiOPF http://tiopf.sourceforge.net/Doc/overview/index.shtml You also might be interested in the G Framework: http://code.google.com/p/g-framework/
The accepted answer does not tell the entire story. Yes, whenever you see zeros, a NULL pointer is involved. That is because NULL is by definition zero. So calling zero NULL may not be saying much. What is interesting about the message you get is the fact that NULL is mentioned twice. In fact, the … Read more
I’m not sure if there’s a “Delphi 2010” way, but there is a Windows way that doesn’t involve FindFirst and all that jazz. I threw together this Delphi conversion of that routine (and in the process modified it to handle > 4GB size files, should you need that). uses WinApi.Windows; function FileSize(const aFilename: String): Int64; … Read more
The main advantage is less onerous type identity rules. Consider: a: array of Integer; b: array of Integer; These two variables are not assignment compatible. It is a compiler error to write: a := b; On the other hand if you use the generic syntax: a: TArray<Integer>; b: TArray<Integer>; then these two variables are assignment … Read more
How do I write a TDBCtrlGrid VCL Style custom class?
You create a named Mutex when you start the application. Check GetLastError to see if an other instance is already running. Put this code right after “begin” in your DPR file. Replace the GUID with one of your own. When I need a text constant that’s unlikely to be used for anything else, I usually … Read more
Object Pascal was an object oriented extension of Pascal developed by Apple. The first version of Delphi was evolved from Turbo Pascal. The object oriented features in Turbo Pascal were, rightly, considered not fit for purpose. So Borland developed Delphi 1 and incorporated much of the Apple Object Pascal language. So the language for the … Read more