Ifelse activity in workflow

Thank you Paul

This was very helpful.

I had one more query.

In the case of the scenario 2 : code condition, if the branching is more than two branches,
how do you invoke the relevant branch from the shared method.

for eg : if the "ifelse" branching is only two branches. then the steps mentioned in your reply(scenario 2 : code condition) is followed and the
Function MethodName(sender as Object, e as EventArgs) as Boolean
{
If <condition>
return true;
else
return false;
}

will branch to the relevant flow based onthe condition value.

In the above scenario if the branching is more than two branches, how do I invoke the relevant branch from the method.

thank you,
BinV

When you specify an IfElse activity, the "If Else" switching is handled by the Workflow engine, you merely need to specify the condition for each branch. So for example, if I create a workflow that needs to branch into two if a PurchaseOrder.Status is "Approved" I would add a condition to the first branch that says (either in code or Rules) "If PurchaseOrder.Status = 'Approved' return true else return false". You don't need to specify a condition for the second branch as it will be called if the prior conditions are false.

You can add more branches by right clicking on the IfElse activity and selecting "Add Branch". This is like creating a switch statement with each branch having its own condition that simply returns true or false. Again, you need not specify the condition for the final branch.

Hope this helps,
Paul

Paul did an excellent job describing this above. Let me just add a simple illustration for you. Take the following workflow snippet for instance:

IfElse
IfElseBranch1
IfElseBranch2
IfElseBranch3

This is logically equivalent to writing the following C# code:

if (x) { } else if (y) { } else // OR "else if(z)" if a conditon was specified for the last branch { }

where x, y, and z are the conditions corresponding to each branch. The workflow will then handle the execution of your rules as needed, e.g. if x returns false, then it will call y and so on until it gets a true or it runs out of branches.

Thanks!
Angel

Hi,

It would be very interesting to offer to developers an other scenario to the condition for an IfElse branch. This new scenario will be based on the support of custom condition.

You can already set the ifElseBranchX Condition to your custom condition in Code or XOML. But, unfortunately, the workflow designer provides by default only the two condition types that you mention.

To workaround this, I developed a custom IfElse branch that "copy-pastes" the code of the Microsoft IfElse branch in adding the support of my custom condition. Unfortunately, this support is hard-coding... A solution will be to list all classes that implement the Condition class, or to provide a "Browse and Select a .NET type" dialog ...

Regards.
Pascal RECCHIA

Hey BinduV,

I have an example of setting up the rule condition in an article at MSBICentral called "WF Activities Part I - Practical Use of ExternalMethod, IfElse & CallExternalMethod Activities". It wires up the IfElse Activity based on a range of zip codes. If the condition is met then the branch is invoked. Else the other branch is invoked. Hope this helps.

Raskal, that sounds exactly like what I need. Unfortunately your blog is down. I tried it from our network and from our web server hosted in the states.

Raskal, I ended up writing an IfElseActivity of my own, due to an additional requirement I had. My requirement was to select multiple conditions for the branch, and I also wanted to pass parameters to the conditions. So I implemented an ifelse activity that takes conditions in the form of activities that implement an interface called IConditionActivity.

You can go have a look and download the solution at: http://dotnet.org.za/hendrik/archive/2006/07/04/53953.aspx