Sharepoint List operations -SPList - Programatically update different column in SPList

Sharepoint List operations :: SPList

Reference a List by its name using the web object[Referenced by current context]

SPSite site = SPContext.Current.Site;
SPWeb web = site.OpenWeb();
SPList DEptList = web.Lists["Departments"]; 

Reference a List Item using its ID

SPListItem  item = DEptList.GetItemById(requestID);

Reference a List Item  filter using a query

SPQuery query = new SPQuery();

query.Query += "<Where><And><Eq><FieldRef Name='Title' />";

query.Query += "<Value Type='Text'>" + role + "</Value></Eq></And></Where>";

SPListItemCollection itemCol = SystemList.GetItems(query);

foreach (SPListItem item in itemCol)

{   
      AdGroup = item["ADGroup"].ToString();

      AdFolder = item["ADFolder"].ToString();

} 

Get value of a column “Single Line Text Column” from an listitem and update a textbox.

txtFax.Text = item["Fax"].ToString();

Get value of a column “People and Group” from an listitem and update a textbox.

char[] charToRemove = { '#', ' ', ';' };

txtNe.Text = item["ReqMgr"].ToString().Remove(0, 3).TrimStart(charToRemove);

 Get multiple users “Names” from People and Groups Column and update a dropdown list

String strFolderOwner = item["Owner"].ToString();

char[] toSplitter = { ';' };

string[] arrOwnerName = strFolderOwner.Split(toSplitter);

for (int i = 1; i < arrOwnerName.Length; i++)

{

string owner = arrOwnerName[i].Substring(arrOwnerName[i].IndexOf("#") + 1);

if ((i % 2) != 0)

    {

         DropFolderOwner.Items.Add(new ListItem(owner, ownerID));

    }

}

Get SPUser value from“People and Group” column.

string strUserValue = item["Head"].ToString(); 

str = strUserValue.Split(';')[0];

deptHeadID = Convert.ToInt32(str);

SPUser depthead = web.AllUsers.GetByID(deptHeadID);

Get value of a column “Date and Time” from an listitem and update a textbox.

string reqDate = item["RequestedDate"].ToString();

DateTime rDate = DateTime.Parse(reqDate);

txtRequestedDate.Text = rDate.ToShortDateString();

 Open and read an attachment from a SPList and using a hyperlink

string fileAttachmentUrl = ""; int attachCount = 0;

attachCount = item.Attachments.Count;

if (attachCount > 0)

{

      SPAttachmentCollection attachCollec = item.Attachments;

      foreach (string fileName in attachCollec)

      {

           fileAttachmentUrl = attachCollec.UrlPrefix + fileName;

           LinkToAttachment.Visible = true;

           LinkToAttachment.Text = "Click here to view " + fileName;

           LinkToAttachment.NavigateUrl = fileAttachmentUrl;

      }

 }

Get value of a column “Yes\No” .

Boolean isVend = (Boolean)item["VAVendor"];

OR

Boolean allResponsed = Convert.ToBoolean(surveyItem["AllResponsesReceived"]);

Get from a “Multiple Choice column"

String str = item["Approval"].ToString();

str = str.Replace("<div>","");str = str.Replace("</div>","");

Check if a column is empty of not.

item["ContactTitle"] != null

For a column of type MultiLine Text also check :

    item["ContactEmail"].ToString() != "<div></div>"

  Add to a column of type string:

SPListItem reqItem = VList.Items.Add();

reqItem["RName"] = currentUser.Name.ToString();

reqItem.Update();

  Add to column of type people and groups:

The user under whose account will have read permissions to the site and contribute permissions to the SharePoint List. So add a “user” to site using escalated privileges and then add to the column.

string Login = "xxx-1\\login”;

SPSecurity.RunWithElevatedPrivileges(delegate()

 {

       using (SPSite elevatedSite = new SPSite(web.Site.ID))

       {

            elevatedSite.AllowUnsafeUpdates = true;

            SPWeb elevatedWeb = elevatedSite.OpenWeb(web.ID);

            {

                  elevatedWeb.AllowUnsafeUpdates = true;

                  SPUser manager = elevatedWeb.EnsureUser(Login);

             }

       }

  });

SPUser mgrToADD = web.AllUsers[managerLogin];

reqItem["ReqMgr"] = mgrToADD;

 Add multiple users to type people and groups.

ArrayList arrUsers = new ArrayList();

PickerEntity UserEntity = new PickerEntity();

SPFieldUserValueCollection fieldUsrValues = new SPFieldUserValueCollection();                  

// GET multiple SIMILAR TO USERs FROM THE PEOPLE PICKER

int UsrCount = UserPicker.Accounts.Count;

for (int j = 0; j < UsrCount; j++)

{

    UserEntity = (PickerEntity) UserPicker.Entities[j];

    UserAcctName = UserEntity.Description;

    Hashtable PeopleEditorData = UserEntity.EntityData;

    string strUserLogin = UserEntity.Key;

    arrUsers.Add(strUserLogin);

}

foreach (object obj in arrUsers)

{

   string login = obj.ToString();

   SPSecurity.RunWithElevatedPrivileges(delegate()

   {

    using (SPSite elevatedSite = new SPSite(web.Site.ID))

    {

      elevatedSite.AllowUnsafeUpdates = true;

      SPWeb elevatedWeb = elevatedSite.OpenWeb(web.ID);

      {

        elevatedWeb.AllowUnsafeUpdates = true;

        SPUser User = elevatedWeb.EnsureUser(login);

        SPFieldUserValue val = new SPFieldUserValue(web,User.ID, User.Name);

        fieldUserValues.Add(val);

       }

      }

     });

   }

reqItem["UserNames"] = fieldUserValues;

Add an attachment to a list item:

if (FileUploadW9.PostedFile != null && FileUploadW9.HasFile)

{

        Stream fStream = FileUploadW9.PostedFile.InputStream;

        byte[] contents = new byte[fStream.Length];

        fStream.Read(contents, 0, (int)fStream.Length);

        fStream.Close();

        fStream.Dispose();

       SPAttachmentCollection attachments = reqItem.Attachments;

        string fileName = Path.GetFileName(FileUploadW9.PostedFile.FileName);

        attachments.Add(fileName, contents);

}

Add to a “Yes\No” columns:

reqItem["AccessSimilarTo"] = true;