TStringBuilder 類別- C++ Builder 2009的新成員

TStringBuilder的出現,意味Codegear有意讓C++ Builder支援.NET了...但一切只是憶測.....

TStringBuilder 類別

include  SysUtils.hpp

Description

Use a TStringBuilder as an editable string.  

The TStringBuilder class is completely compatable with the .Net framework's StringBuilder (MSDN) class. Use a TStringBuilder instance to hold a character array. This array can be modified after creation. Substrings can be appended, searched and replaced, or inserted. The character array can be queried by index or converted to a string for comparison.  

The character array can be referenced directly by using the Chars property. The Length property contains the current length of the character array.  

builder.Length = builder.ToString.Length;  

The Capacity property holds the current allocated storage space for this TStringBuilder instance. Capacity can be increased up to the value of MaxCapacity and down to the current value of Length. Capacity is increased if Length is increased, or the character array is altered by appending to increase it's length.  

The Append method converts a multitude of possible types to a string and appends that to the current character array. AppendFormat allows you to append several objects to the character array, each object with it's own format.  

The Equals method compares a specified object or another TStringBuilder to this instance of TStringBuilder.  

The Append, CopyTo, Insert, Remove and Replace methods access the character array by index or search the character as a string. The ToString method converts the character array to a string to provide string functionality.  

TStringBuilder is an implementation of the .NET StringBuilder (MSDN) class.  

C++ Examples: 

 /*

This example exercises many of the members of the TStringBuilder class.

*/

template

void testAppend(T t)
{
    std::auto_ptr builder(new TStringBuilder());
    builder->Append(t);
    UnicodeString s1 = builder->ToString();
    UnicodeString s2(t);
    assert(s1 == s2);

}

#if defined(_DELPHI_STRING_UNICODE)

const wchar_t* ext_chars =

    L"А Б Ð’ Г Д Є Ж Ð… З И І"
    L"К Л Ðœ Н О П Ò€ Ð  Ð¡ Т Ѹ"
    L"Ф Ð¥ Ñ  Ð¦ Ч Ш Щ Ъ Ы Ь Ñ¢"
    L"Ю ІА Ѧ Ѩ Ѫ Ѭ Ñ® Ñ° Ѳ Ñ´ Ѥ";
#else

const char* ext_chars =

    "À Á Â Ã Ä Ã… Æ Ç È É Ê Ë ÃŒ Í ÃŽ Ï"
    "Ð Ñ Ã’ Ó Ô Õ Ö × Ø Ù Ú Û Ãœ Ý Þ ß"
    "à  Ã¡ â ã ä Ã¥ æ ç è é ê ë ì í î ï"
    "ð ñ ò ó ô õ ö ÷ ø ù ú û ü ý þ ÿ";
#endif

//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)
{
    {
        // Test starts out as empty
        std::auto_ptr builder(new TStringBuilder());
        assert(builder->ToString() == System::String());
    }
  

   {
        // Append
        short s = 0xffe;
        testAppend(s);
        unsigned short us = 0xfffe;
        testAppend(us);

    }

    {

        const _DCHAR* p = ext_chars;

        std::auto_ptr builder(new TStringBuilder());
        System::String str1(p);

        // Appending of wchar_t

        while (*p) 
        {
            builder->Append(*p++);
        }

        // Length property

        assert(builder->Length == str1.Length());

        // Subscript operator

        for (int i=0; i
        {
            // NOTE: strings are 1-based
            assert((*(builder.get()))[i] == str1[i+1]);
        }

        // ToString()

        System::String str2 = builder->ToString();
        Edit1->Text = str1;
        Edit2->Text = str2;
        assert(str2 == str1);

        // Replace

        builder->Replace(' ', '.');
        UnicodeString str3;
        str3 = builder->ToString();
        Edit3->Text = str3;
        assert(str3 != str2);

        // Replace back

        builder->Replace(L'.', L' ');
        System::String str4 = builder->ToString();
        Edit4->Text = str4;
        assert(str2 == str4);
    }

    {
        System::String str(ext_chars);
        std::auto_ptr builder(new TStringBuilder());
        // Insert at start when empty, at start when not empty and at end

        builder->Insert(0, str);
        builder->Insert(0, str);
        builder->Insert(builder->Length, str);

        // Concatenate string 3 times

        System::String str2;
        str2 += str;
        str2 += str;
        str2 += str;

        str = builder->ToString();
        Edit5->Text = str;
        assert(builder->ToString() == str2);
    }

    MessageDlg("All assertions passed in the TStringBuilder Test test.",
        mtInformation, TMsgDlgButtons() <<>

}

//---------------------------------------------------------------------------

void __fastcall TForm1::Button2Click(TObject *Sender)
{
    const _DCHAR* p = ext_chars;
    std::auto_ptr builder(new TStringBuilder());

    // Appending of chars

    while (*p) 
    {
        builder->Append(*p++);
    }

    System::String str1(ext_chars);
    System::String str2 = builder->ToString();
    assert(str1 == str2);

    builder->Replace(_D(" "), _D("."));
    System::String str3;
    str3 = builder->ToString();
    assert(str1 != str3);

    builder->Replace(_D("."), _D(" "));
    System::String str4(builder->ToString());
    assert(str1 == str4);
    MessageDlg("All assertions passed in the TStringBuilder Replace test.",
        mtInformation, TMsgDlgButtons() <<>

}