============================================
using Microsoft.SharePoint;

SPWeb site = SPControl.GetContextWeb(Context);
SPListItemCollection items = site.Lists["ListName"].Items;

SPListItem item = items.Add();

item["Field_1"] = OneValue;

item["Field_2"] = TwoValue;

item.Update();

删除sharepoint list数据
=============================================
using Microsoft.SharePoint;

SPWeb site = SPControl.GetContextWeb(Context);

SPListItemCollection items = site.Lists["ListName"].Items;

items[0].Delete();

上传文件到sharepoint
=============================================
using System.IO;

using Microsoft.SharePoint;

if( htmlInputFile1.PostedFile != null )
{
          SPWeb site = new SPSite(destinationURL).OpenWeb();
          Stream stream = htmlInputFile1.PostedFile.InputStream;

          byte[] buffer = new bytes[stream.Length];

          stream.Read(buffer, 0, (int) stream.Length);

          stream.Close();

          site.Files.Add(destinationURL, buffer);
}

查询记录及更新数据
===============================================
using Microsoft.SharePoint;

SPWeb web = new SPSite("http://nick").OpenWeb("test");  //Open website

web.AllowUnsafeUpdates = true;

SPList list = web.Lists["ListName"];

SPQuery query = new SPQuery();

query.Query = "<Where>"+
          "<And><And>"+
          "<Eq><FieldRef Name=\"Filed_1\"/><Value Type=\"Text\">Test</Value></Eq>" +
          "<Eq><FieldRef Name=\"Filed_2\"/><Value Type=\"Text\">" + (string)OneValue + "</Value></Eq>" +
          "</And>"+
          "<Eq><FieldRef Name=\"Filed_3\"/><Value Type=\"Text\">" + (string)TwoValue + "</Value></Eq>" +
          "</And>"+
          "</Where>";

query.RowLimit = 10;

//查询
SPListItemCollection items = list.GetItems(query);
try
{
  if (Items.Count != 0)
  {
     //更新sharepoint list 数据
     foreach (SPListItem list in listItems)
     {
         list["Filed_1"] = TextBox1.text.ToString();
         list["Filed_2"] = TextBox2.text.ToString();
         list["Filed_3"] = TextBox3.text.ToString();

         listItem.Update();
     }                      
  }
  else
  {   //将数据记录添加进sharepoint
      SPListItem addlist = List.Items.Add();

      addlist["Filed_1"] = TextBox1.Text.ToString();
      addlist["Filed_2"] = TextBox2.Text.ToString();
      addlist["Filed_3"] = TextBox3.Text.ToString();

      addlist.Update();
  }
}
catch
{
 ...
}