SharePoint Exception: Coercion Failed: Input cannot be null for this coercion

This is the exception, I am seeing very first time in SharePoint development. What I tried was, through SharePoint designer I tried to update the list item. The source and destination lists are having a field of type choice. I want to grab the choice field information from source list and update the destination list choice field.
The problem occurs only when the source choice field is empty.

More clearly, I have a list with checkbox list field. When a new list item is added, the workflow triggers and start updating the another list item with the current item information. And when I select nothing in the checkbox list field, then it throws the exception "SharePoint Exception: Coercion Failed: Input cannot be null for this coercion".

So, why the problem comes?
Because in update list item phrase in SharePoint designer I have selected the lookup for choice Return field as as Choices, Comma delimited. See the below screenshot.

Once changed that back to the As String then everything worked perfect. But, didn't get the reason behind. When nothing selected, then it shouldn't do any operation. It should check for null and do nothing. May be a built-in problem or something interesting with this.

Hope this helps to understand it well and solve your problem. Read More...

SharePoint list view web part wildcard search

I know, most of the SharePoint developers are looking for this. As everyone knows we can do partial search on data view web part by passing a parameter to it and by using the expression "contains" we can implement partial search on a field or column. But, when you come to list view web part you can't pass the parameters [There is no support for list view web part like web part parameters] and no way we can implement the partial keyword search. Today I have spent time on it to solve this problem with the help of my colleague Durga and found a wonderful way. This is giving really wonderful result and doing wild card search even on very big document libraries fast. Below are the steps I followed to solve this. [I will post detailed post on it with screen shots and nice explanation soon in this blog.]

• Created an ASPX web part page in a SharePoint site.
• Added two web parts to the page. One is for content editor web part and another is for list view web part of a SharePoint library or list.
• Now, open the page in IE browser and add a text box, button to the content query web part.
• Written simple logic to button click event of the button and reload the page with the below formatted url. The url should be of the format

"you aspx page url?FilterName=FieldName&FilterMultiValue=*valuefromtextbox*".

• In above url, we are using two key value pairs to solve our problem.
• First one is FilterName: which is for in which field of the list view we need to search the value. For example the value may be Title, ID etc…
• Second one is the FilterMultiValue: Which is for what is the value we need to search. i.e. keyword. So, here you can pass multiple values too separated by semi-colon ';'.
• So, example url should like this
• http://mosssite/pages/listviewcustomwildcardsearch.aspx?FilterName=Title&FilterMultiValue=*prav* 
• Now the above url will search all the records in the given list view for the keyword "prav". So, wherever it exists in the given field name it will return all records.

Then how it is working?
Generally, If you research on query strings for a list view web part, it expects some query strings to filter and sort. I am SharePoint developer and got to know the two query strings which SharePoint list view web part uses for filtering. FilterName and FilterMultiValue. So, with that my research continued and tried long time with so many operators like %, single quotes, double quotes etc… in the value of the FilterMultiValue. Finally, I tried with * character before and end of the keyword, there I succeeded. Example: *prav* to FilterMultiValue.

• That’s it…. Working simply great.
• With that, You are done implementing the wild card search in a column in list view web part.

Happy by doing SharePoint customization. I know, this will solve so many problems to SharePoint dev’s.  Isn’t it? Please let me know if you have any questions, issues and write your valuable feedback and comments.

Will post more descriptive explanation of this post with screenshots soon in this blog. Follow me!!!

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Creating RESTful Mashups using SPD 2007

Fantastic article on creating Mashups in SharePoint. Complete description step to step with images. Thanks for the great stuff. You can see the article here.

http://blogs.msdn.com/sharepointdesigner/archive/2008/12/05/creating-restful-mashups-using-spd-2007-part-1.aspx

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Show data from list by using web services through SharePoint designer

When working on big SharePoint projects we will get really good requirements and most of them are the challenging. In some cases we need to show the data by pulling from one list in a site to another site. For example, on “Site A” home page we want to show the data from another site or sub site. Then we need to use the web services and call the list and get the items. This is what this blog post is completely about.

How is it useful?

It is useful because as far as i know we have two ways of doing this without coding.

1. By using IFrames on the web pages. Create a content editor web part on the page of the site where you want to show the list content and add a IFrame and point it to the page where list data is present in another web site. So it is just doing nothing, just loading that page as it is. But it’s not a right way of implementing it. Because if authentication is different then you need to login to the site 2 times. One for the main site and another for the IFrame. Another problem is we can’t use IFrames on the web pages for security and performance issues. So it’s not a good way of doing. Then is there any other way?

2. Yes, We have a solution for this and it’s the better way of implementing it. Call a web services by connecting to the web services of the site we want to get the data, pass credentials and then select the list or library you want. Add a web part to the page and give the list we pulled from web service to the web part. That’s it. It is the easy and efficient way. I am explaining this a little bit detail below.

• Create a SharePoint web part page for showing content by using web services.
• Open the page in SharePoint designer and detach it from page layout.
• Now, we need to add a web part for showing the data. We have a very comfortable and most usable web part in SharePoint nothing but Data View web part. Add this to the page.
• Now, web part is ready and need of data source. So we need to go for list where we have to pull the data. It can be in the current site, sub site or some other site.       
• Go to Task pane menu item of SharePoint designer and select the Data Source Library. Now you are able to see the all the data sources exist in the current site only. For example, if you want to pull data from a list which is in subsite or some other site you can’t find the data source entry in the lists and libraries section. This is the time where we need to go for XML web services. See above figure for more details.
• Now we need to add a new XML web service data source to our site. How difficult it will be? very simple, follow below.
• Expand the node XML web services and you can find the link called “Connect to a web service”.
• Now you are open up with a window where you can see the properties of the web service data source.Now we need to set the properties for the data source. Move to the tag General. Fill the name, description and keywords. 
• Move to tab source and fill the source description location. You can browse to the location of the site and add the which asmx file you want to add. Or if you know location you can manually enter the url. Usually the location is like this. http://sharepointserver/_vti_bin/lists.asmx?WSDL
• Remember for example purpose, i given the lists.asmx file path, you can use any of available web service.
• Before click on Connect now button, check the credentials. You have options for entering credentials, or use default/windows credentials or don’t ask for credentials etc. Set the credentials type and then say Connect now.

• Now the command to configure. Our case, we want to show the data. So it should be the Select operation.
• Select the port : ListsSoap [default one]
• Select operation type : GetListItems
• Now time to pass parameters to the data source. First thing is you need to select the listname parameter that from which list you need to get the data.You can pass parameters to the web service to filter the results too.  For example, if your list has the boolean column for IsUpdated. Then we want to show only the columns which are having IsUpdated=false, then you can set that here. We are done with configuring and setting the data source properties.
• We have data source ready and we need to use it to link to the data view web part.
• If you set everything correct, then you can see the entry under the XML web service section.
• Click on the data source and choose Show data from the menu.
• Now, it will open Data Source Details task pane that pull all the column information from the list that you connected to as shown below.

Select the  list of columns that you want to show on the page. [You can select multiple columns by pressing the control key.]

• Now click on the option “Insert selected fields as” Multiple Item view. It will add all the selected columns to the Dataview web part.
• Save the page and view it in browser.

How nice it is, and how simple it is?

Really thanks to SharePoint designer and Data view web part that makes our work easier.

Please post comments if you have any questions.

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