Type validation when updating a DataRow

Question

I am trying to validate types when updating a DataRow. I am using the following code:

        public static int Write<T>(T data, DataRow row, string FieldName)
        {
        if (null == data)
        {
            row[FieldName] = row.Table.Columns[FieldName].DefaultValue;
        }
        else
        {
            if (row.Table.Columns[FieldName].DataType is T)
            {
                row[FieldName] = data;
                return 0;
            }
            else
            {
                try
                {
                    row[FieldName] = (row.Table.Columns[FieldName].DataType)Convert.ChangeType(data, row.Table.Columns[FieldName].DataType);
                }
                catch (InvalidCastException)
                {
                    return 1;
                }
            }
        }
        return 0;
    }

But it's not working. On the if row.Table.Columns[FieldName].DataType is T I compared a GUID column with a GUID and returned false. The part (row.Table.Columns[FieldName].DataType)Convert.ChangeType(data, row.Table.Columns[FieldName].DataType); I have a syntax error, the (row.Table.Columns[FieldName].DataType) is not working.

I am open to another type of validation.