Gentle中的数据表实体类相关自定义属性的设置和获得

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
=========================================
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
------------------------------------






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
------------------------------------






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
--------------------------------------






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
------------------------------------






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
------------------------------------------






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
).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;




}