Working with versions in List programmatically

Hi All,

Our SharepointKings team really wanted to share this because when we needed this kind of facility we did not find many articles on this topic. so we thought to dig in this and find out something.

Ok, let's get to the business straight forward. The requirement was to have History for the List. Yes, a history for the list.

So bottom line is working with versions in List programmatically.

So we thought that there is a default facility in Document Library for Version and it is very famous for versions, but we actually never came across list history. so we decided to look on the List Settings and yes we were right, we found that there is an option to have version for the List also.

To Enable the Versions, Go to List Settings and go to Version Settings and then Select Create a version each time you edit an item in this list? to true. there you go, you have just made versoning option on.

Now, Try to edit any item from that list and then Select the ECB of that Item, see you will find Version History option, Click on that and you will see all changes that you have just performed. So this is very nice for the End User.

But, What about the Developer if they have to do it by code and display the result of any previous version????
So this article focuses on this.

Let me give you a brief introduction on what all classes we will require to get this thing done.

Let's consider a scenario where you need to check all versions of all ListItems in the List.

First you take an object of the list in which you need to find our the versions of ListItems.

Considering that i am writing code in Web Part, change the code accordingly (If Needed).

SPList objList = SPContext.Current.Web.Lists["{your_list}"];

SPQuery objQuery = new SPQuery();

objQuery.Query = "<Where><Gt><FieldRef Name=\"ID\"/><Value Type=\"Counter\">0</Value></Gt></Where>";

SPListItemCollection objItemColl = objList.GetItems(objQuery);

Note that update your code accordingly in single line. here code is written in multiple lines only for readability.

Here what we have done is we got all ListItems so far for the list.

Now, we will proceed in getting the versions of each ListItem.

foreach (SPListItem objItem in objItemColl)
{

SPListItemVersionCollection objVerisionColl = objItem.Versions;

//Above Line gets all versions of the ListItem. If it returns 1, that means nothing is modified. no version //for this item.

if (objVerisionColl.Count > 1)
{
//Navigate to each version of the ListItem
foreach (SPListItemVersion objVersion in objVerisionColl)
{
int versionID = objVersion.VersionId;

//Returns incremental IDs starting from 512,1024,1536... for each version

DateTime timeofcreation = objVersion.Created;

//VersionLabel - Gets 1.0,2.0,3.0 as default versions for each iteration

string strVersionLabel = objVersion.VersionLabel;

SPListItem objLstItm = objVersion.ListItem;

}
}
}

This means If the ListItem is modified for 3 times, the above loop for that ListItem will execute 3 times and you will get the VersionId as 512,1024,1536 Likewise. VersionLabel as 3.0, 2.0, 1.0. It returns by default from latest to oldest.

So This is the way to get all versions of the ListItem. So now the question is how to get the Data of old versions.Check out the last line in the loop which actually gets the SpListItem of that Version.

So first get the SPListItem that you want and then check for all versions just like the above code and use simple technique to retrieve the data. Consider i have three columns. FirstName, LastName and Address in the List.

So all i have to do is, once i get the Version that i want to fetch take its SPListItem object and then access its fields,

string strFirstName = Convert.ToString(objLstItm["FirstName"]);
string strLastName = Convert.ToString(objLstItm["LastName"]);
string strAddress = Convert.ToString(objLstItm["Address"]);

Now you have the old version data on your hand. Play with it on your own way!!!!