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近期开发项目中用到的编码小技巧汇总说明
1.默认EF生成的连接字符串比较的长和怪异，若想使用普通的连接字符串来连接EF，则可以通过创建分部类，并重写一个构造函数，在构造函数中通过动态拼接EntityConnectionString得到EF所需的连接字符串，具代实现代码如下：
public partial class DataEntities { private static ConcurrentDictionary<string, string> entityConnStrings = new ConcurrentDictionary<string, string>(); public DataEntities(string connName) : base(BuildEntityConnectionString(connName)) { } private static string BuildEntityConnectionString(string connName) { if (!entityConnStrings.ContainsKey(connName)) { var connStrSetting = System.Configuration.ConfigurationManager.ConnectionStrings[connName]; EntityConnectionStringBuilder entityConnStrBuilder = new EntityConnectionStringBuilder(); entityConnStrBuilder.Provider = connStrSetting.ProviderName; entityConnStrBuilder.ProviderConnectionString = EncryptUtility.DesDecrypt("XXXXX", connStrSetting.ConnectionString); entityConnStrBuilder.Metadata = "res://*/Data.csdl|res://*/Data.ssdl|res://*/Data.msl"; string entityConnString = entityConnStrBuilder.ToString(); entityConnStrings.AddOrUpdate(connName, entityConnString, (key, value) => entityConnString); } return entityConnStrings[connName]; } }注意上面的类是一个分部类：partial，同时BuildEntityConnectionString方法是一个静态方法，在BuildEntityConnectionString方法中ProviderConnectionString = EncryptUtility.DesDecrypt("XXXXX", connStrSetting.ConnectionString);是关键，我这里是对config中的连接字符串 也都进行了加密，故此处我需要解密，若无这个需求可以直接：ProviderConnectionString =connStrSetting.ConnectionString即可。后续实例化EF上下文对象时，请使用：DataEntities(string connName)这个构造涵数即可，DataEntities是具体的EF上下文对象，大家的EF上下文类名均可能不相同。
2.支持一个通用对象的XML序列化（即：一个类中有可变类型属性成员，需要不同的序列结果及生成不同的序列元素名称），具体实现代码如下：
一个需要被序列化成XML的类：其中要求生成的XML元素detail必需有子元素，且子元素名称及子元素内部属性根据类型的不同而不同（即：detail元素下的子元素是可变的）
[XmlRootAttribute("master")] public class DemoMaster<T> where T : class { [XmlElement("attr")] public string DemoAttr { get; set; } [XmlElement("detail")] public DemoDetail<T> DemoDetail { get; set; } //关键点在这里，该属性元素为：detail，但其子元素根据T不同而不同 } public class DemoDetail<T> : IXmlSerializable where T : class { public T body { get; set; } public System.Xml.Schema.XmlSchema GetSchema() { return null; } public void ReadXml(System.Xml.XmlReader reader) { string bodyStr = reader.ReadInnerXml(); this.body = XmlHelper.XmlDeserialize<T>(bodyStr, Encoding.UTF8); } public void WriteXml(System.Xml.XmlWriter writer) { writer.WriteRaw(XmlHelper.XmlSerialize(this.body, Encoding.UTF8, true)); } } [XmlTypeAttribute("list-a", AnonymousType = false)] public class DemoDetailA { public string Apro1 { get; set; } public string Apro2 { get; set; } public string Apro3 { get; set; } } [XmlTypeAttribute("list-b", AnonymousType = false)] public class DemoDetailB { public string Bpro1 { get; set; } public string Bpro2 { get; set; } public string Bpro3 { get; set; } } [XmlTypeAttribute("list-c", AnonymousType = false)] public class DemoDetailC { public string Cpro1 { get; set; } public string Cpro2 { get; set; } public string Cpro3 { get; set; } }注意上面代码中，需要关注：DemoDetail属性及DemoDetail<T>类，DemoDetail属性仅是为了生成detail元素节点，而子节点则由DemoDetail<T>类来进行生成，DemoDetail<T>是实现了IXmlSerializable接口，在XML序列化时，DemoDetail<T>类仅将body属性对应的T类型实例内容进行序列化（WriteRaw），而反序列化时，则先反序列化body属性对应的T类型实例，然后赋值给body属性，这也是巧妙之处，DemoDetail<T>类本身并没有真正参与到序列化中，故序列化的字符串也看不到DemoDetail<T>类相关的元素，DemoDetail<T>类仅仅是一个XML序列化格式生成的中介。序列化的XML结果如下：
序列化代码：
var demo1 = new DemoMaster<DemoDetailA>() { DemoAttr = "demo1", DemoDetail = new DemoDetail<DemoDetailA>() { body = new DemoDetailA() { Apro1 = "demoA1", Apro2 = "demoA2", Apro3 = "demoA3" } } }; var demo2 = new DemoMaster<DemoDetailB>() { DemoAttr = "demo2", DemoDetail = new DemoDetail<DemoDetailB>() { body = new DemoDetailB() { Bpro1 = "demoB1", Bpro2 = "demoB2", Bpro3 = "demoB3" } } }; var demo3 = new DemoMaster<DemoDetailC>() { DemoAttr = "demo3", DemoDetail = new DemoDetail<DemoDetailC>() { body = new DemoDetailC() { Cpro1 = "demoC1", Cpro2 = "demoC2", Cpro3 = "demoC3" } } }; textBox1.Text = XmlHelper.XmlSerialize(demo1, Encoding.UTF8); textBox1.Text += "\r\n" + XmlHelper.XmlSerialize(demo2, Encoding.UTF8); textBox1.Text += "\r\n" + XmlHelper.XmlSerialize(demo3, Encoding.UTF8);序列化的XML:
<?xml version="1.0" encoding="utf-8"?><master> <attr>demo1</attr> <detail><list-a> <Apro1>demoA1</Apro1> <Apro2>demoA2</Apro2> <Apro3>demoA3</Apro3></list-a></detail></master><?xml version="1.0" encoding="utf-8"?><master> <attr>demo2</attr> <detail><list-b> <Bpro1>demoB1</Bpro1> <Bpro2>demoB2</Bpro2> <Bpro3>demoB3</Bpro3></list-b></detail></master><?xml version="1.0" encoding="utf-8"?><master> <attr>demo3</attr> <detail><list-c> <Cpro1>demoC1</Cpro1> <Cpro2>demoC2</Cpro2> <Cpro3>demoC3</Cpro3></list-c></detail></master>
3.winform DataGridView 实现指定列采取密码框模式显示与编辑，以及列绑定到复合属性（即：绑定到多层次属性），具体实现代码如下：
dataGridView1.CellFormatting += new DataGridViewCellFormattingEventHandler(dataGridView1_CellFormatting); dataGridView1.EditingControlShowing += new DataGridViewEditingControlShowingEventHandler(dataGridView1_EditingControlShowing); public string EvaluateValue(object obj, string property) { string retValue = http://www.mamicode.com/string.Empty;".")) { e.Value = http://www.mamicode.com/EvaluateValue(dataGridView1.Rows[e.RowIndex].DataBoundItem, dataGridView1.Columns[e.ColumnIndex].DataPropertyName);"KeyCode") { if (e.Value != null && e.Value.ToString().Length > 0) { e.Value = http://www.mamicode.com/new string(‘*‘, e.Value.ToString().Length);"KeyCode") { usePassword = true; } TextBox txt = e.Control as TextBox; if (txt != null) { txt.UseSystemPasswordChar = usePassword; } }//示例：绑定的源数据类定义 public class DemoBindClass { public string Attr { get; set; } public string KeyCode { get; set; } public DemoDetailA Detail { get; set; } } public class DemoDetailA { public string Apro1 { get; set; } public string Apro2 { get; set; } public string Apro3 { get; set; } public DemoDetailB DetailChild { get; set; } } public class DemoDetailB { public string Bpro1 { get; set; } public string Bpro2 { get; set; } public string Bpro3 { get; set; } }绑定到数据源：
var demo = new[] { new DemoBindClass() { Attr = "demo", KeyCode="a123456789b", Detail = new DemoDetailA() { Apro1 = "demoA1", Apro2 = "demoA2", Apro3 = "demoA3", DetailChild = new DemoDetailB() { Bpro1 = "demoB1", Bpro2 = "demoB2", Bpro3 = "demoB3" } } } }; dataGridView1.AutoGenerateColumns = false; dataGridView1.DataSource = demo;实现指定列采取密码框模式显示与编辑，以及列绑定到复合属性均需要订阅DataGridView的CellFormatting及EditingControlShowing事件，并在其中写转换当前Cell的Value，实现列绑定到复合属性，关键点在：EvaluateValue方法，该方法逻辑很简单，就是根据绑定的属性层级（.分隔）层层遍历获取属性的值，直到遍历完或为空时停止，最后得到的结果即是绑定的属性的值。最终实现的效果如下图示：
近期开发项目中用到的编码小技巧汇总说明