Workbook.ChangeFileAccess Method

Changes the access permissions for the workbook. This might require an updated version to be loaded from the disk.

Namespace: Microsoft.Office.Tools.Excel
Assembly: Microsoft.Office.Tools.Excel (in

public virtual void ChangeFileAccess (
	XlFileAccess Mode,
	[OptionalAttribute] Object WritePassword,
	[OptionalAttribute] Object Notify



One of the XlFileAccess values. Specifies the new access mode.


Specifies the write-reserved password if the file is write reserved and Mode is xlReadWrite. Ignored if there is no password for the file or if Mode is xlReadOnly.


true to notify the user if the file cannot be immediately accessed.

If you have a file open in read-only mode, you do not have exclusive access to the file. If you change a file from read-only to read/write, Microsoft Office Excel must load a new copy of the file to ensure that no changes were made while you had the file open as read-only.

Optional Parameters

For information on optional parameters, see Understanding Optional Parameters in COM Interop.

The following code example displays a message if the ReadOnlyRecommended property is true and the ReadOnly property is false, and then prompts the user to set the file access to read-only by calling the ChangeFileAccess method.

private void MakeWorkbookReadOnly()
    if (this.ReadOnlyRecommended && !this.ReadOnly)
        // Change the access level of the document to read-only if the user 
        // clicks yes.
        if (MessageBox.Show("Set this document to read-only?",
            "Sample", MessageBoxButtons.YesNo) == DialogResult.Yes)
                missing, false);