Title: Load a CSV file in Excel in C#

Loading a CSV file (comma-separated value file) into Excel isn't too hard once you know the tricks. Using the same tricks you can load a file that uses any delimiter, not just a comma.

First at design time, add a reference to the Microsoft.Office.Interop.Excel library.

To make using the library easy, add the following using statement at the top of your code.

using Excel = Microsoft.Office.Interop.Excel;

This lets you use the word Excel to mean Microsoft.Office.Interop.Excel in your code.

The example uses the following code to open the CSV file.

// Open a delimited file in Excel. private void btnLoad_Click(object sender, EventArgs e) { // Get the Excel application object. Excel.Application excel_app = new Excel.ApplicationClass(); // Make Excel visible (optional). excel_app.Visible = true; // Open the file. excel_app.Workbooks.Open( txtFile.Text, // Filename Type.Missing, Type.Missing, Excel.XlFileFormat.xlCSV, // Format Type.Missing, Type.Missing, Type.Missing, Type.Missing, txtDelimiter.Text, // Delimiter Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); }

The code first creates an instance of the Excel application. It then uses that object's Workbooks.Open method to open the file. The tricks here are:

• Set the format to xlCSV
• Indicate the delimiter (commas, tabs, semicolons, or whatever)
• Use Type.Missing for any parameter that you want to omit from the method call

That's all there is to this example. Once you have the file open, you could use other Excel methods to manipulate the data. For example, you could copy values into other workbooks, save the data in a new file, or load the data into your C# program.

If you try to type a Tab into the delimiter text box, the program moves the focus to the button and ignores the Tab character. To use Tab as a delimiter, copy a Tab from Word or some other program and then paste it into the text box.

Download the example to experiment with it and to see additional details.