Update Sharepoint List Item

I got following error…

System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.SharePoint.SPListItem.get_UniqueId()
at ConsoleApplication1.Program.Main(String[] args) in Program.cs:line 21

running following code

using (SPSite site = new SPSite("http://site/"))
{    
    using (SPWeb web = site.OpenWeb())
    {
        try
        {
            SPList list = web.Lists["ListName"]; // 2        
            SPListItem item = list.Items.Add();
            Guid itemId = item.UniqueId;
            SPListItem itemUpdate = web.Lists["ListName"].Items[itemId];
            itemUpdate["PercentComplete"] = .45; // 45%        
            itemUpdate.Update();
        }
        catch (Exception e)
        { 
            Console.WriteLine(e);
            Console.ReadLine();

        }
    }
}

What’s the problem?

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

If you’re trying to alter values for a just inserted list item, you should go with:

SPList list = web.Lists["ListName"];
//SPListItem item = list.Items.Add();
//item["PercentComplete"] = .45; // 45%
//item.Update();

SPListItemCollection items = list.GetItems(new SPQuery()
{
    Query = @"<Where>
                <Eq>
                   <FieldRef Name='Title' />
                   <Value Type='Text'>Desigining</Value>
                </Eq>
              </Where>"
});

foreach (SPListItem item in items)
{
    item["PercentComplete"] = .45; // 45%
    item.Update();
}

You just need to use list.Items[uniqueId] or faster list.GetItemByUniqueId(uniqueId) if you needs to find a particular item to update; what can be accomplished by using SPQuery class.

Method 2

Ruben’s answer was correct but was getting few errors (may be its was only for me) therefore i tweaked little bit and then it was working fine. Below is the code which i used if anyone needs it

 SPList list = web.Lists["ListName"];
                    //SPListItem item = list.Items.Add();
                    //item["PercentComplete"] = .45; 
                    // 45%//item.Update();
                   SPQuery oQuery = new SPQuery();

                        oQuery.Query = @"<Where>               
                                    <Eq>                   
                                        <FieldRef Name='Title' />                   
                                        <Value Type='Text'>Design</Value>              
                                    </Eq>            
                                  </Where>";
                        SPListItemCollection collListItems = list.GetItems(oQuery);
                        foreach (SPListItem item in collListItems)
                    {    item["PercentComplete"] = .55;   
                        item.Update();}

Method 3

Try calling Update () on the list before getting the UniqueID

 SPList list = web.Lists["ListName"]; // 2        
 SPListItem item = list.Items.Add();
 item["Title"] = "Test";
 item.Update ();
 list.Update ();
 Guid itemId = item.UniqueId;

Method 4

My best quess is that your item is not yet created in the list when you do:

Guid itemId = item.UniqueId;
SPListItem itemUpdate = web.Lists["ListName"].Items[itemId];

First do a item.Update() before requesting the uniqueId and/or getting the item back from a list.

PS : I see no reason why you should get a second SPItem object for updating the ‘PercentComplete’ information.


All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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