Delphi枚举设备使用代码_PHP教程

现在的 delphi(2010、xe) 已经自带了 directx 的相关单元(...sourcertlwin).
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//枚举函数
function directsoundenumerate(
lpdsenumcallback: tdsenumcallback; //回调函数
lpcontext: pointer //用户指针
): hresult; stdcall; //返回错误代码, 成功则返回 s_ok(0)

//directsoundenumerate 需要的回调函数的原形:
tdsenumcallback = function(
lpguid: pguid; //设备的 guid
lpcstrdescription: pchar; //设备描述
lpcstrmodule: pchar; //模块标识
lpcontext: pointer //由 directsoundenumerate 提供的用户指针
): bool; stdcall; //返回 true 表示要继续枚举, 不在继续找了就返回 false

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这是常见的代码:
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unit unit1;

interface

uses
windows, messages, sysutils, variants, classes, graphics, controls, forms,
dialogs, stdctrls;

type
tform1 = class(tform)
listbox1: tlistbox; //只在窗体上放了一个列表框
procedure formcreate(sender: tobject);
end;

var
form1: tform1;

implementation

{$r *.dfm}

uses directsound; //!

function enumcallback(lpguid: pguid; lpcstrdescription, lpcstrmodule: pchar;
lpcontext: pointer): bool; stdcall;
begin
form1.listbox1.items.add(lpcstrdescription);
result := true;
end;

procedure tform1.formcreate(sender: tobject);
begin
directsoundenumerate(enumcallback, nil);
end;

end.

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在回调函数中直接使用窗体控件不好, 修改如下:
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uses directsound;

function enumcallback(lpguid: pguid; lpcstrdescription, lpcstrmodule: pchar;
lpcontext: pointer): bool; stdcall;
begin
tstrings(lpcontext).add(lpcstrdescription);
result := true;
end;

procedure tform1.formcreate(sender: tobject);
begin
directsoundenumerate(enumcallback, listbox1.items);
end;

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获取更多信息:
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uses directsound;

function enumcallback(lpguid: pguid; lpcstrdescription, lpcstrmodule: pchar;
lpcontext: pointer): bool; stdcall;
begin
if lpguid <> nil then tstrings(lpcontext).add(guidtostring(lpguid^));
tstrings(lpcontext).add(lpcstrdescription);
if lpcstrmodule <> nil then tstrings(lpcontext).add(lpcstrmodule);
tstrings(lpcontext).add(emptystr);
result := true;
end;

procedure tform1.formcreate(sender: tobject);
begin
directsoundenumerate(enumcallback, listbox1.items);
end;

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