App.config中内容：
<?xml version="1.0" encoding="utf-8" ?> <configuration> <!-- <system.windows.forms jitDebugging="true" //允许调试 />--> <appSettings> <add key="setInterval" value="1000"/> <add key="chooseCOM" value="COM4"/> <add key="senStr" value="R"/> </appSettings> </configuration>
读取App.config中chooseCOM内容,并把COM4改为COM1：
string setCOM = ConfigurationSettings.AppSettings["chooseCOM"];
ConfigHelper.SetValue("chooseCOM"," COM1");//
设置app.config键值的方法：
public static class ConfigHelper { public void SetValue(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"); } }