[Automation To .Net] Find String In Solution

Hi All,
I am making a automation program which auto compile and fix error.
Now, when I have a problem like this :

Old Code In VS 2003 or 6.0:

Code:

---

for(int i = 0; i < 10; ++i)
{
    cout<<i;
}
cout<<i;

---

My program will auto update it to :

Code:

---

int i;
for(i = 0; i < 10; ++i)
{
    cout<<i;
}
cout<<i;

---

okie, I had foreach file in project and used Regex to do it.
But, the problem is its so slowly.

I want to get it better so I start to use Find function.
But I doesn't work.
I had been around for 2 days and get nothing.
So I post here my problem and hope someone will help me.

Thank in advance.
KidKid.

It would be more helpful if you included the code that did the find and replace.