Edit file content - file-io

Question

In Form1 I have 2 TextBoxes(surname and name). When I push the "register" button I write them into a file through TextWriter. Every line contains surname and name, So there are 2 fields per line.
In Form2 I want to edit them by asking a parameter. For example in Form2 I have one TextBox. If the surname I type into the TextBox is equal to one from my file, i want to show surname and name in correct TextBoxes in Form1, and after editing surname or name I want to overwrite previous line in the correct place by pushing the "register" button.
Thanks to user Medinoc I write the file like this:
ref class MyClass
{
public:
String^ cognome;
String^ nome;
};
//...
List<MyClass^>^ primo = gcnew List<MyClass^>();
//...
MyClass^ myObj = gcnew MyClass();
myObj->cognome = textBox1->Text;
myObj->nome = textBox2->Text;
primo->Add(myObj);
//...
TextWriter ^tw = gcnew StreamWriter(L"primoAnno.txt", true);
for each(MyClass^ obj in primo)
{
//You can use any character or string as separator,
//as long as it's not supposed to appear in the strings.
//Here, I used pipes.
tw->Write(obj->cognome);
tw->Write(L"|");
tw->Write(obj->nome);
}
tw->Close();
READ
MyClass^ ParseMyClass(String^ line)
{
array<String^>^ splitString = line->Split(L'|');
MyClass^ myObj = gcnew MyClass();
myObj->cognome = splitString[0];
myObj->nome = splitString[1];
return myObj;
}
Hope I was clear enough. I'm not english.
Thanks in advance!!

Answer 1

It's still classic text file editing behavior:
What you need is a function to search for a particular line in the file; and another function to modify a particular line. That one will be similar to the deleting code.
Find:
MyClass^ FindMyClass(String^ surnameToFind)
{
MyClass^ found = nullptr;
TextReader^ tr = gcnew StreamReader(L"primoAnno.txt");
String^ line;
while(found == nullptr && (line=tr->ReadLine()) != nullptr)
{
MyClass^ obj = ParseMyClass(line);
if(obj->cognome == surnameToFind)
found = surnameToFind;
}
tr->Close();
}
Update:
MyClass^ objToUpdate = gcnew MyClass;
objToUpdate->cognome = textBox1->Text;
objToUpdate->nome = textBox2->Text;
TextWriter^ tw = gcnew StreamWriter(L"primoAnno2.txt", true);
TextReader^ tr = gcnew StreamReader(L"primoAnno.txt");
String^ line;
bool updated = false;
while((line=tr->ReadLine()) != nullptr)
{
MyClass^ obj = ParseMyClass(line);
if(obj->cognome == objToUpdate->cognome)
{
line = objToUpdate->cognome + L"|" + objToUpdate->nome;
updated = true;
}
tw->WriteLine(line);
}
//If the surname was not in the file at all, add it.
if(!updated)
{
line = objToUpdate->cognome + L"|" + objToUpdate->nome;
tw->WriteLine(line);
}
tr->Close();
tw->Close();
File::Delete(L"primoAnno.txt");
File::Move(L"primoAnno2.txt", L"primoAnno.txt");