1.自定义 表名属性 TableNameAttribute
2.自定义 主键属性 PrimaryKeyAttribute
3.自定义 列名属性 TableColumnAttribute
4.数据表person对应的实体类person.cs
5.获得person.cs类型实体 对应的表名及字段名
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下面的属性代码文件 都直接建立在App_Code下 以方便使用
1.自定义 表名属性 TableNameAttribute
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using System;/**//// <summary>
/// TableNameAttribute 的摘要说明
/// </summary>[AttributeUsage( AttributeTargets.Class, AllowMultiple=false, Inherited=true )]public sealed class TableNameAttribute : Attribute
{ private string name; private string schema; //private CacheStrategy cacheStrategy = GentleSettings.DefaultCacheStrategy;
/**//// <summary> /// The constructor for the TableName attribute. /// </summary>
/// <param name="name">The name of the database table used to store instances of this class.</param> public TableNameAttribute( string name ) { this.name = name; } /**//// <summary> /// The constructor for the TableName attribute. /// </summary> /// <param name="name">The name of the database table used to store instances of this class.</param> /// <param name="strategy">The cache stratgey to use for instances of this type. <see /// cref="CacheStrategy"/> for a list of available options.</param> //public TableNameAttribute( string name, CacheStrategy strategy ) //{ // this.name = name; // this.cacheStrategy = strategy; //} /**//// <summary> /// The name of the database table used to store instances of this class. /// </summary> public string Name { get { return name; } } /**//// <summary> /// The optional schema name with which to prefix the table name in queries. /// This value overrides the default schema definition (if present) in the /// configuration file. Note: this property is currently unused. /// </summary> public string Schema { get { return schema; } set { schema = value; } } /**////// <summary> ///// The cache behavior for objects of this type. <see cref="CacheStrategy"/> ///// for a list of available options. ///// </summary> //public CacheStrategy CacheStrategy //{ // get { return cacheStrategy; } // set { cacheStrategy = value; } //}}2.自定义 主键属性 PrimaryKeyAttribute
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using System;/**//// <summary>/// PrimaryKeyAttribute 的摘要说明/// </summary>[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = true, Inherited = true)]public sealed class PrimaryKeyAttribute : Attribute{ private bool autoGenerated = false; /**//// <summary> /// Set this property to true for primary keys that are automatically assigned /// by the database on insert (identity columns in SQL server terminology). /// </summary> public bool AutoGenerated { get { return autoGenerated; } set { autoGenerated = value; } }}3.自定义 列名属性 TableColumnAttribute
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using System;using System.Data;/**//// <summary>/// TableColumnAttribute 的摘要说明/// </summary>[AttributeUsage( AttributeTargets.Property | AttributeTargets.Field, AllowMultiple=false, Inherited=true )]public class TableColumnAttribute : Attribute{ private string name; private bool notNull; private int size; private bool hasDbType = false; // true when DbType property has been set private long dbType; private object nullValue = null; private bool handleEnumAsString = false; private bool isReadOnly = false; private bool isUpdateAfterWrite = false; /**//// <summary> /// Constructor for table columns that are named after their property counterpart /// and whose value cannot be null. /// </summary> public TableColumnAttribute() : this(null, true) { } /**//// <summary> /// Constructor for table columns that are named after their property counterpart. /// </summary> /// <param name="notNull">A boolean telling whether null values are allowed in the database</param> public TableColumnAttribute(bool notNull) : this(null, notNull) { } /**//// <summary> /// Constructor for table columns whose value cannot be null. /// </summary> /// <param name="name">The name of the database column</param> public TableColumnAttribute(string name) : this(name, true) { } /**//// <summary> /// Constructor for table columns. /// </summary> /// <param name="name">The name of the database column</param> /// <param name="notNull">A boolean telling whether null values are allowed in the database</param> public TableColumnAttribute(string name, bool notNull) { this.name = name; this.notNull = notNull; } /**//// <summary> /// The name of the database column for storing the property decorated with this attribute. /// </summary> public string Name { get { return name; } } /**//// <summary> /// This property (defaults to true) can be used to specify whether NULL values are /// allowed in the database. This allows the framework to fail early if a constraint /// is violated. /// </summary> public bool NotNull { get { return notNull; } set { notNull = value; } } /**//// <summary> /// The database type of the field in the database. Beware that the DbType enumeration /// values are NOT the ones used by the individual providers. Gentle does NOT convert /// the DbType to a "best match" for the provider. It is therefore recommended that /// you use the DatabaseType below until a better type definition system is available. /// </summary> [Obsolete("Please use DatabaseType instead.")] public DbType DbType { get { return (DbType)dbType; } set { hasDbType = true; dbType = (long)value; } } /**//// <summary> /// The database type of the field in the database. Convert the actual database type /// enumeration to a long by casting it in the declaration. /// </summary> public long DatabaseType { get { return dbType; } set { hasDbType = true; dbType = value; } } /**//// <summary> /// The size or length of the field in the database. String properties will be clipped /// to fit. /// This feature will obsoleted once Gentle is capable of extracting type and size /// information directly from the database. If specified, the values must match /// those extracted from the database (when implemented). /// </summary> public int Size { get { return size; } set { size = value; } } /**//// <summary> /// This property indicates whether a DbType was specified. This construct is necessary /// because the DbType enum has no value for undefined. /// </summary> public bool HasDbType { get { return hasDbType; } } /**//// <summary> /// Obsolete, use NullValue instead. /// </summary> [Obsolete("Use NullValue instead.")] public object MagicValue { get { return nullValue; } set { nullValue = value; } } /**//// <summary> /// This value of this property is used when a column is NotNull and the property value /// is null. If this is undefined the framework will throw an error for NotNull columns /// whose values are null. /// </summary> public object NullValue { get { return nullValue; } set { nullValue = value; } } NullValue Helper Properties for VB.NET Users#region NullValue Helper Properties for VB.NET Users /**//// <summary> /// This property allows type-safe setting of the NullValue for VB users. /// </summary> public int NullValue_int { set { NullValue = value; } } /**//// <summary> /// This property allows type-safe setting of the NullValue for VB users. /// </summary> public NullOption NullValue_opt { set { NullValue = value; } } #endregion /**//// <summary> /// This value indicates that the column should not be set on insert and update. It is /// primarily useful for columns that are set internally by the database. /// </summary> public bool IsReadOnly { get { return isReadOnly; } set { isReadOnly = value; } } /**//// <summary> /// This value indicates that the column must be read after each insert and update. It is /// primarily useful for columns that are set internally by the database. Note that using /// this feature (by setting this to true for any column) will significantly impact /// performance for the worse, as for every update/insert another select will be /// performed. Also, fields will be updated using reflection after select, which is also /// quite slow (depending on the number of columns). /// </summary> public bool IsUpdateAfterWrite { get { return isUpdateAfterWrite; } set { isUpdateAfterWrite = value; } } /**//// <summary> /// If member which has this attribute attached is enum then this property /// indicates wheter framework saves it as string or as integer. /// Default is false, ie enums are saved as integers /// </summary> public bool HandleEnumAsString { get { return handleEnumAsString; } set { handleEnumAsString = value; } }}public enum NullOption{ /**//// <summary> /// <type>.MinValue will be stored as NULL, and NULL will be read as <type>.MinValue. /// </summary> MinValue, /**//// <summary> /// <type>.MaxValue will be stored as NULL, and NULL will be read as <type>.MaxValue. /// </summary> MaxValue, /**//// <summary> /// 0 (or the equivalent for other numeric types) will be stored as NULL, and NULL will be read as 0. /// </summary> This value can only be used with numeric types (such as decimal). Zero, /**//// <summary> /// Guid.Empty will be stored as NULL, and NULL will be read as Guid.Empty. This value can only be /// used with Guid fields. /// </summary> EmptyGuid}4.数据表person对应的实体类person.cs
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using System;using System.Data;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;/**//// <summary>/// person 的摘要说明/// </summary>[TableName("person")]public class person{ public person() { } //[TableColumn("personID", NotNull = true), PrimaryKey] protected int _personID; //[TableColumn("personName", NotNull = true)] protected string _personName = String.Empty; [TableColumn("personID", NotNull = true), PrimaryKey] public int PersonID { get { return _personID; } set { _personID = value; } } [TableColumn("personName", NotNull = true)] public string PersonName { get { return _personName; } set { _personName = value; } }}5.获得person.cs类型实体 对应的表名及字段名
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protected void Button1_Click(object sender, EventArgs e){ person aPerson = new person(); aPerson.PersonID = 22; aPerson.PersonName = "zhangsan"; Type aType = aPerson.GetType(); //类实体公开属性对应的列名属性 PropertyInfo[] aPropertyInfos = aType.GetProperties(); string strPublicProperty = " "; for (int i = 0; i < aPropertyInfos.Length; i++) { PropertyInfo aPropertyInfo = (PropertyInfo)aPropertyInfos[i]; strPublicProperty += i.ToString() + " : 实体属性名 " + aPropertyInfo.Name; strPublicProperty += " 对应值 " + aPropertyInfo.GetValue(aPerson, null).ToString() + " "; object[] attrs = aPropertyInfo.GetCustomAttributes(typeof(TableColumnAttribute), true); for (int m = 0; m < attrs.Length; m++) { strPublicProperty += " 对应列名 " + ((TableColumnAttribute)attrs[m]).Name; } } this.TextBox1.Text = strPublicProperty; //FieldInfo[] aFieldInfos = aType.GetFields(); //string strPublicField = " "; //for (int j = 0; j < aFieldInfos.Length; j++) //{ // FieldInfo aFieldInfo = (FieldInfo)aFieldInfos[j]; // strPublicField += j.ToString() + " : " + aFieldInfo.Name + " "; //} //this.TextBox2.Text = strPublicField; //类实体对应的表名属性 string strTablePKName = " "; object[] attrsAA = aType.GetCustomAttributes(typeof(TableNameAttribute), true); for (int n = 0; n < attrsAA.Length; n++) { strTablePKName += " " + ((TableNameAttribute)attrsAA[n]).Name; } //类实体对应的主键属性 MemberInfo[] aMemberInfos = aType.GetMembers(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance); string strMemberInfo = " "; for (int k = 0; k < aMemberInfos.Length; k++) { MemberInfo aM = aMemberInfos[k]; object[] attrs = aM.GetCustomAttributes(typeof(PrimaryKeyAttribute), true); for (int m = 0; m < attrs.Length; m++) { strTablePKName += " 主键 " + aM.Name; } } this.TextBox2.Text = strTablePKName; }
