RichTextBox.LoadFile Method (String)
Loads a rich text format (RTF) or standard ASCII text file into the RichTextBox control.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
When loading a file with the LoadFile method, the contents of the file being loaded replace the entire contents of the RichTextBox control. This will cause the values of the Text and Rtf properties to change. You can use this method to load a previously created text or RTF document into the control for manipulation. If you want to save the file, you can use the SaveFile method.
With this version of the LoadFile method, if the file being loaded is not an RTF document, an exception will occur. To load a different type of file such as an ASCII text file, use the other versions of this method that accept a value from the RichTextBoxStreamType enumeration as a parameter.
The following code example opens an RTF file into the RichTextBox control. The example uses the OpenFileDialog class to display a dialog to request the file from the user. The code then loads that file assuming that it is an RTF document file. If the file is not, the example code will throw an exception. This example requires that the code is placed in a Form class that has a RichTextBox control named richTextBox1.