[RESOLVED] Preventing window from freezing in .net Framework 3.5

I have a process that's taking long time and the window freezes until the operation finishes. Here's my code:

button function

VB.NET Code:

...
proc = new Process
{
    StartInfo = new ProcessStartInfo
    {
        FileName = "install.bat",
        // Arguments = "command line arguments to your executable",
        UseShellExecute = false,
        RedirectStandardOutput = true,
        CreateNoWindow = true
    }
};
proc.Start();
while (!proc.StandardOutput.EndOfStream)
{
    string line = await proc.StandardOutput.ReadLineAsync();
    // do something with line
    info_lbl.Text = line;
}
...

Here ReadLineAsync is underlined with red line and telling me I can't use ReadLineAsync.

ReadLineAsync was added in .NET 4.5. The Task class didn't even get added until .NET 4.0. In .NET 3.5, you could use a BackgroundWorker or implement your own multi-threading.

That works like a charm. Thanks a lot!