Why are elements from data sources not transferred to wpf constructs?

Question

WPF

Tell me, I created a WPF project, connected the DLL in the links, I add an object from the class in the data sources, and I can not drag the element into the constructor. What am I doing wrong?

Answer 1

Well the manual from microsoft says so
"When you drag an element from the Data Sources window into the WPF Designer, Visual Studio creates a XAML object that defines a new data-bound control (or binds an existing control to a data source). for some sources Data Visual Studio also generates code in the code-behind file that populates the data source with data."
Wanted to try