So what does REST on Excel Services look like???

Shahar — Wed, 28 Oct 2009 16:00:00 GMT

In my first post about Excel Services and REST, I showed how to construct a simple REST URL pointing directly to a PNG in a workbook. This post was supposed to be about the discovery built into the Excel Services REST API. However, I got a couple of questions about what my previous post actually looks like visually when used inside SharePoint 2010 and so I decided to post about that today instead. People like shiny screenshots.. :)

In the previous post, I gave the following example of a REST URL:

http://server/_vti_bin/ExcelRest.aspx/Shared Documents/Bugs.xlsx/Model/Charts(‘PersonalBugChart’)

In this post, I will show how a similar URL is used to post a chart about my alleged bug status into a SharePoint blog and have the chart be tied directly to the Excel file in which it resides.

First off – here’s what the chart looks like in Excel:

If you click the image you will see that the chart is called “PersonalBugs”. The actual location of the file is at “http://tssrva/sites/sp2009/shared documents/bugs.xlsx”. That means that the link to the chart inside Excel would be:

http://tssrva/_vti_bin/ExcelRest.aspx/sites/sp2009/shared documents/Bugs.xlsx/Model/Charts(‘PersonalBugs’)

The next step would be to create a blog post in SharePoint – when creating the blog entry, you can choose the “Insert” tab from the ribbon and then choose “From Address”:

Once you click address, all you need to do is put in the URL to the chart:

Once you hit OK, you will immediately see the chart appear within the blog post editor:

Hitting the Submit button will post the blog entry:

The real neat part then becomes that as the workbook changes (due to external data being refreshed, the spreadsheet itself being modified and saved etc), everybody will see the changes directly on the blog the next time they come in!

I hope the shiny screenshots made everything clearer.

Next up: Discovery!!

Using C# 3.0 Extension Methods to make life easier when using optional parameters in Office PIAs

Shahar — Fri, 29 Feb 2008 20:00:27 GMT

Gabhan Berry (read his blog - he has lots of Excel programmability related information in there!) wrote a piece about how to make using optional parameters a little less painful when using C# to program against the Excel (and any other) COM PIA object model.

While his solution makes life much easier in some scenarios, after reading the post, there were a few things that bothered me from a fragility of code point of view about his solution - specifically, the various issues with type safety (parameters and method names). While the mechanism he presents will work properly, I was thinking if I could come up with something that will not have those issues. I think I was able to come up with something, but it has it's own set of issues. The biggest one is the fact that it only works with C# 3.0 - not with 2.0. That said, here's the solution:

OverGen is a tool I wrote that will take an assembly and find all methods in it that are optional and then generate overloads for all those methods that will allow the user to pass in a smaller amount of parameters. For each optional parameter a method has, an extension method will be generated.

Extension Methods are basically a very simple compiler construct that allows a class to extend another class by way of adding methods to it - the extension is very superficial - no methods are actually added to the class but rather, the compiler knows that when such a method is called on class, it will try and find it in supporting classes.

Here's an example of one of the methods generated by the tool:

public static Microsoft.Office.Interop.Excel.Workbook Open(this Microsoft.Office.Interop.Excel.Workbooks @__thisParam,

string Filename) {

return @__thisParam.Open(

Filename,

System.Type.Missing,

System.Type.Missing);

}

Notice the "this" keyword on the first parameter? That's what makes this method an extension method. If you did not have this guy, this is what ANY call to .Open would have to look like, even if you only use the first parameter:

app.Workbooks.Open("c:\\temp\\file.xlsx", Type.Missing, Type.Missing,

Type.Missing, Type.Missing, Type.Missing, Type.Missing,

Type.Missing, Type.Missing, Type.Missing, Type.Missing);

And here's what the code looks like if you are using the extension method shown above:

app.Workbooks.Open("c:\\temp\\file.xlsx");

That's about it - you should be able to do this for every method that takes optional parameters.

You can download the OverGen tool to enable you to create such extension method for every PIA you use.

You can also download ready-made extension methods for Excel and Word.

Cum Grano Salis : Excel

So what does REST on Excel Services look like???

Using C# 3.0 Extension Methods to make life easier when using optional parameters in Office PIAs