设置配置文件的某个节点的值

public static void SetConnectionStringsKeyValue(string AppKey, string AppValue)
       {
           XmlDocument xDoc = new XmlDocument();
           xDoc.Load(System.Windows.Forms.Application.ExecutablePath + ".config");

           XmlNode xNode;
           XmlElement xElem1;
           XmlElement xElem2;

           xNode = xDoc.SelectSingleNode("//connectionStrings");

           xElem1 = (XmlElement)xNode.SelectSingleNode("//add[@name='" + AppKey + "']");
           if (xElem1 != null) xElem1.SetAttribute("connectionString", AppValue);
           else
           {
               xElem2 = xDoc.CreateElement("add");
               xElem2.SetAttribute("name", AppKey);
               xElem2.SetAttribute("connectionString", AppValue);
               xNode.AppendChild(xElem2);
           }
           xDoc.Save(System.Windows.Forms.Application.ExecutablePath + ".config");
       }

       public static void SetAppSettingsKeyValue(string AppKey, string AppValue)
       {
           XmlDocument xDoc = new XmlDocument();
           xDoc.Load(System.Windows.Forms.Application.ExecutablePath + ".config");

           XmlNode xNode;
           XmlElement xElem1;
           XmlElement xElem2;

           xNode = xDoc.SelectSingleNode("//appSettings");

           xElem1 = (XmlElement)xNode.SelectSingleNode("//add[@key='" + AppKey + "']");
           if (xElem1 != null) xElem1.SetAttribute("value", AppValue);
           else
           {
               xElem2 = xDoc.CreateElement("add");
               xElem2.SetAttribute("key", AppKey);
               xElem2.SetAttribute("value", AppValue);
               xNode.AppendChild(xElem2);
           }
           xDoc.Save(System.Windows.Forms.Application.ExecutablePath + ".config");
       }

配置文件如下：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <connectionStrings>
    <add name="ConnString" connectionString="" />
  </connectionStrings>

  <appSettings>
    <add key="AdminPwd" value=""/>
    <add key="GridAlterRowBackColor" value="-2627631"/>  
  </appSettings>

  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0"/>
  </startup>

 </configuration>

读取某个值：

static int GetGridSetting()
        {
            int iReadColor = 0;
            object oResult = System.Configuration.ConfigurationManager.AppSettings["GridAlterRowBackColor"];
            if (!Common.IsNullOrEmptyObject(oResult))
            {
                iReadColor = Convert.ToInt32(oResult.ToString());
            }

            return iReadColor;
        }

       public static bool IsNullOrEmptyObject(object oSource)
       {
           if (oSource != null)
           {
               return string.IsNullOrEmpty(oSource.ToString());
           }           
           return true;
       }

XML操作总结

c# 读取xml某个节点的值的方法

​​http://shirlly.iteye.com/blog/414203​​

C# 读取XML文件某个节点的值