bsp;$0008 Reference to a dynamically allocated
UNICODE string.
varDispatch $0009 Reference to an OLE automation object
(an IDispatch interface pointer).
VarError $000A Operating system error code.
varBoolean $000B 16-bit boolean (type WordBool).
varVariant $000C Variant (used only with variant arrays).
varUnknown $000D Reference to an unknown OLE object
(an IUnknown interface pointer).
varByte $0011 8-bit unsigned integer (type Byte).
VarString $0100 Reference to a dynamically-allocated long string
(type AnsiString).
varTypeMask $0FFF Bit mask for extracting type code. This constant
is a mask that can be combined with the VType
field using a bit-wise AND..
varArray $2000 Bit indicating variant array. This constant is a
mask that can be combined with the VType field
using a bit-wise AND to determine if the variant
contains a single value or an array of values.
VarByRef $4000 This constant can be AND''''d with Variant.VType
to determine if the variant contains a pointer to
the indicated data instead of containing the data
itself.
范例 var
V1, V2, V3, V4, V5: Variant;
I: Integer;
D: Double;
S: string;
begin
V1 := 1; { Integer value }
V2 := 1234.5678; { Real value }
V3 := ''''Hello world''''; { String value }
V4 := ''''1000''''; { String value }
V5 := V1 +V2 +V4; { Real value 2235.5678 }
I := V1; { I = 1 }
D := V2; { D = 1234.5678 }
S := V3; { S = ''''Hello world'''' }
I := V4; { I = 1000 }
S := V5; { S = ''''2235.5678'''' }
end;
-----------------------------------------------------------------------------
VarArrayOf 建立一个简单的一维variant array
-----------------------------------------------------------------------------
Unit System
函数原型 function VarArrayOf(const Values: array of Variant): Variant;
范例 var
A:Variant;
begin
A:=VarArrayOf([1 ,10 ,''''Hello ,10000]);
S:=A[1]+'''' ''''+IntToStr(A[2]);
Label1.Caption:=S;
end;
-----------------------------------------------------------------------------
VarArrayRedim 重定variant阵列中高维部分的高注脚.
-----------------------------------------------------------------------------
Unit System
-----------------------------------------------------------------------------
函数原型 procedure VarArrayRedim(var A: Variant; HighBound:Integer);
-----------------------------------------------------------------------------
VarArrayDimCount 传回Variant阵列的维数.
-----------------------------------------------------------------------------
Unit System
函数原型 function VarArrayDimCount(const A: Variant): Integer;
-----------------------------------------------------------------------------
VarArrayHighBound 传回Variant阵列中一维的高注脚.
-----------------------------------------------------------------------------
Unit System
函数原型 function VarArrayHighBound(const A: Variant; Dim: Integer):Integer;
-----------------------------------------------------------------------------
VarArrayLowBound 传回Variant阵列中一维的低注脚.
-----------------------------------------------------------------------------
Unit System
函数原型 function VarArrayLowBound(const A: Variant; Dim: Integer):
Integer;
范例 procedure TForm1.Button1Click(Sender: TObject);
var
A:Variant;
Count:Integer;
HighBound:Integer;
LowBound:Integer;
i:Integer;
S:String;
begin
A:=VarArrayCreate([0,5, 1,3],varVariant);
Count:=VarArrayDimCount(A);
S:=#13+''''维数:''''+IntToStr(Count)+#13;
for i:=1 To Count do
Begin
HighBound:=VarArrayHighBound(A,i);
LowBound:=VarArrayLowBound(A,i);
S:=S+''''HighBound: ''''+IntToStr(HighBound)+#13;
S:=S+''''LowBound : ''''+IntToStr(LowBound)+#13;
End;
ShowMessage(S);
end;
-----------------------------------------------------------------------------
VarArrayLock 将variant阵列==>指定给一阵列变数.
-----------------------------------------------------------------------------
VarArrayUnLock 解除上述的指定.
-----------------------------------------------------------------------------
Unit System
函数原型 function VarArrayLock(var A: Variant): Pointer;
函数原型 procedure VarArrayUnlock(var A: Variant);
范例 procedure TForm1.Button1Click(Sender: TObject);
Const
HighVal=12;
type
TData=array[0..HighVal, 0..HighVal] of Integer;
var
A:Variant;
i,j:Integer;
Data:^TData;
begin
A:=VarArrayCreate([0,HighVal, 0,HighVal],varInteger);
for i:=0 to HighVal do
for j:=0 to HighVal do
A[i,j]:=i*j;
Data:=VarArrayLock(A);
for i:=0 to HighVal do
for j:=0 to HighVal do
Grid1.Cells[i+1,j+1]:=IntToStr(Data^[i,j]);
VarArrayUnLock(A);
end;
-----------------------------------------------------------------------------
VarIsArray 传回Variant是否为一个阵列.
-----------------------------------------------------------------------------
Unit System
函数原型 function VarIsArray(const V: Variant): Boolean;
VarIsEmpty 传回Variant是否尚未注册.(空的)
Unit System
函数原型 function VarIsEmpty(const V: Variant): Boolean;
范例 procedure TForm1.Button1Click(Sender: TObject);
var
A:Variant;
S:String;
begin
A:=VarArrayCreate([0,5, 0,7],varVariant);
if VarIsEmpty(A) Then
S:=''''True''''
else
S:=''''False'''';
Label1.Caption:=S;
end;
-----------------------------------------------------------------------------
** S:=False,A以经建立了.
-----------------------------------------------------------------------------
VarIsNull 传回Variant是否为NULL.
-----------------------------------------------------------------------------
Unit System
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