Assembly: mscorlib (in mscorlib.dll)
An attempt was made to set the property to null.
An attempt was made to set the property to a multidimensional array or to a single-dimensional array with a length that is not exactly 7.
The DateTimeFormatInfo object is read-only.
If setting this property, the array must be one-dimensional and must have exactly seven elements.
If a custom format string includes the format specifier "ddd", DateTime.ToString returns the value of the appropriate element of the array in place of "ddd" in the format string.