Hi! I am using the BinaryReader class in System.IO namespace (in C# of course) for reading data from a file. It's very fast (can read 1,000,000 bytes in less than a second) but I'm using a DataGridView control to show them in my form and (as you may know) it is very absurd! it is highly slow and can change that "less than a second" to about twenty seconds!!! I'm searching for fastest way to show these data in my form. Thanks a lot for your helping. My code's like this: Code: using System.IO; void Fill_DataGridView1_using_BinaryReader(string path) { BinaryReader br = new BinaryReader(path); for (int i = 0; i < length(path); i++) DataGridView1.Rows.Add(br.ReadChars(10 /* for example */)); } I examined this code too but nothing changed! Code: using System.IO; void Fill_DataGridView1_using_BinaryReader_#2(string path) { BinaryReader br = new BinaryReader(path); List<string> data = new List<string>(); for (int i = 0; i <= length(path); i++) data.Add(br.ReadChar()); // 0.4 seconds passed for (int i = 0; i < data.Length; i++) DataGridView1.Rows.Add(data[i]); // 20.4 seconds passed!!! }