At compile time DefaultValueAttribute will likely not influence the created IL and it won't be go through to initialize the property to that value (see DefaultValue attribute is not dealing with my Automobile Property). So your DataContext for "video_length_textbox" is ready to itself, and also your IncrementingTextBox class does not https://aiplsector88gurgaon.finance.blog/2025/05/14/experience-elegant-living-at-jms-floors-manesar-gurgaon/