WPF Interview Questions

Question: What is the base class in WPF (Not .net framework base class)? DispatherObject DependencyObject UIElement Visual Answer: Base class is DispatcherObject. This class is used to provide Thread Affinity features of the WPF controls and Thread affinity needed to overcome the complex global locking mechanism. Question: Which Layout in WPF is most performant? Grid Canvas StackPanel All of the above Answer: Canvas , since we already know the position where to place the control  so position calculation in layout phases are not required. Question: In Layout phase of WPF, how many passes of Logical Tree happened? 1 2 0 … Click here to continue…..

Types of Workflow

There are two types of workflow Sequential Workflow: A Sequential workflow runs from beginning to end, with the workflow engine initiating each step. State Machine Workflow:  A State Machine workflow is driven by external events and user interaction, and simply constrains or interacts with those events, so it stores state between events. State Machine workflows are called this because they allow the developer to define custom “states” that the process can be in at any time.

Components of Workflow

Workflow Runtime Engine:  Every running workflow instance is created and maintained by an in-process runtime engine that is commonly referred to as the workflow runtime engine. Host Process:  When a workflow model is compiled, it can be executed inside any Windows process including console applications, forms-based applications, Windows Services, ASP.NET Web sites, and Web services Runtime Services:  Each service provides a feature that interacts with system outside the workflow. Runtime Services provide features that interact with the Runtime Engine i.e. Persistence, Tracking, Scheduling Base Activity Library: Out-of-Box activities and base for custom activities library Custom Activity Library: Custom Activities derive from Base Activity Library. … Click here to continue…..

What is a Workflow?

A Workflow is a set of activities, which is stored as model and they depict a process. Below figure depicts clearly the difference between Workflow and Activity. Every task is an activity and group of activity depicts a complete workflow. Workflow is run by the Workflow runtime engine. Work Flow Foundation Architecture Workflow model can be written in pure .NET code, pure XAML or Mix of XAML and .NET Code. A workflow model is compiled and can execute under windows, ASP.NET, Web services or windows services application. “Workflow is the operational aspect of a work procedure: how tasks are structured, … Click here to continue…..

What are different types of Workflow in Windows Workflow foundation?

There are two basics type of workflow Sequential Workflow and State machines workflow. A sequential workflow has clear start and finish boundaries. Workflow controls execution in Sequential workflow. In sequential execution, one task is executed after other. Sequential workflow is more rigid in format and execution path has a determistic nature. A State machine workflow is more dynamic in nature. Workflow has states and the state waits for events to help it move to next state. In State machine execution path is undetermestic nature. Below figure shows visual conceptualization of fundamentals. You can see in Sequential workflow the execution path … Click here to continue…..