检查字符串是否为有效的数字

///////Begin Source

function IsNumber(mStr: string): Boolean; { 返回字符串是否是正确的数字表达 }

var

I: Real;

E: Integer;

begin

Val(mStr, I, E);

Result := E = 0;

E := Trunc(I);

end; { IsNumber }

function IsInteger(mStr: string): Boolean; { 返回字符串是否是正确的整数表达 }

var

I: Integer;

E: Integer;

begin

Val(mStr, I, E);

Result := E = 0;

E := Trunc(I);

end; { IsInteger }

///////End Source

///////Begin Demo

procedure TForm1.Button1Click(Sender: TObject);

begin

CheckBox1.Checked := IsNumber(Edit1.Text);

CheckBox2.Checked := IsInteger(Edit1.Text);

end;

///////End Demo