C# open a file for reading and writing

The Read a text file section of this article describes how to use the StreamReader class to read a text file. The Write a text file example 1 and the Write a text file example 2 sections describe how to use the StreamWriter class to write text to a file. The following code uses the StreamReader class to open, to read, and to close the text file.

You can pass the path of a text file to the StreamReader constructor to open the file automatically. The ReadLine method reads each line of text, and increments the file pointer to the next line as it reads. When the ReadLine method reaches the end of the file, it returns a null reference.

For more information, see StreamReader Class. On the File menu, point to New , and then select Project. On the Debug menu, select Start to compile and to run the application. Download Microsoft Edge More info. Contents Exit focus mode.

Is this page helpful? Please rate your experience Yes No. Any additional feedback? Submit and view feedback for This product This page. Write info, 0, info. The file path needs to be changed to a file that exists on the computer in this method. Text; using System. Tasks; using System. Windows; using System. Controls; using System.

GetBytes UserInput. Open filename, FileMode. Seek 0, SeekOrigin. End ; await SourceStream. WriteAsync result, 0, result. The File Stream uses the asynchronous method to perform resource-intensive file operations without blocking the main thread. This performance consideration is particularly important in a Windows 8. FileStream buffers input and output for better performance.

Note This method uses the Disk files which always support random access. At the time of construction, the CanSeek property value is set to true or false depending on the underlying file type. Otherwise, the CanSeek property value is false.

This type of method Implement the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly.

To dispose of it indirectly, use a language construct such as using in C or Using in Visual Basic. The IsAsync property detects whether the filehandle was opened asynchronously. You specify this value when you create an instance of the FileStream class using a constructor that has an isAsync, useAsync, or options parameter.

The Seek method supports random access to files. This is done with byte offset reference point parameters. The byte offset is relative to the seek reference point, which can be the beginning, the current position, or the end of the underlying file, as represented by the three members of the SeekOrigin enumeration in this method. Posted by M. Microsoft Excel is powerful spreadsheet tool with lots of features for data visualization, analysis and documentation.

Excel formats data in the form of rows and columns and cells. As a developer, many times you are required to read or write data into an Excel file. There are multiple ways to read and write data in excel programmatically i. Excel 16 object in our application.