linq to xml

        //添加XML元素
        private void button2_Click(object sender, EventArgs e)
        {
            XElement xe = XElement.Load(strPath);
            IEnumerable<XElement> elements1 = from element in xe.Elements("People")
                                              select element;
            //生成新的编号
            string str = (Convert.ToInt32(elements1.Max(element => element.Attribute("ID").Value)) + 1).ToString("000");
            XElement people = new XElement(
                "People", new XAttribute("ID", str),
                new XElement("Name", textBox11.Text),
                new XElement("Sex", comboBox1.Text),
                new XElement("Salary", textBox12.Text)
                );
            xe.Add(people);
            xe.Save(strPath);
            getXmlInfo();
        }

 //修改XML元素
        private void button3_Click(object sender, EventArgs e)
        {
            if (strID != "")
            {
                XElement xe = XElement.Load(strPath);
                IEnumerable<XElement> elements = from element in xe.Elements("People")
                                                 where element.Attribute("ID").Value == strID
                                                 select element;
                if (elements.Count() > 0)
                {
                    XElement newXE = elements.First();
                    newXE.SetAttributeValue("ID", strID);
                    newXE.ReplaceNodes(
                        new XElement("Name", textBox11.Text),
                        new XElement("Sex", comboBox1.Text),
                        new XElement("Salary", textBox12.Text)
                        );
                }
                xe.Save(strPath);
            } 
            getXmlInfo();
        }

 //删除XML元素
        private void button4_Click(object sender, EventArgs e)
        {
            if (strID != "")
            {
                XElement xe = XElement.Load(strPath);
                IEnumerable<XElement> elements = from element in xe.Elements("People")
                                                 where element.Attribute("ID").Value == strID
                                                 select element;
                if (elements.Count() > 0)
                    elements.First().Remove();
                xe.Save(strPath);
            }
            getXmlInfo();
        }

 //显示选中XML节点的详细信息
        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            strID = dataGridView1.Rows[e.RowIndex].Cells[3].Value.ToString();
            XElement xe = XElement.Load(strPath);
            IEnumerable<XElement> elements = from PInfo in xe.Elements("People")
                                             where PInfo.Attribute("ID").Value == strID
                                             select PInfo;
            foreach (XElement element in elements)
            {
                textBox11.Text = element.Element("Name").Value;
                comboBox1.SelectedItem = element.Element("Sex").Value;
                textBox12.Text = element.Element("Salary").Value;
            }
        }