This code sample demonstrates how to copy class properties from one class to another even if they are not the same type. It also demonstrates how to validate a class's required properties dynamically. Both of these can increase your coding productivity especially when dealing with web service versions of your business classes.
| PropertyHandler.cs | |
using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using System.Diagnostics;
namespace MyApplication
{
public class PropertyHandler
{
#region Set Properties
public static void SetProperties(PropertyInfo[] fromFields,
PropertyInfo[] toFields,
object fromRecord,
object toRecord)
{
PropertyInfo fromField = null;
PropertyInfo toField = null;
try
{
if (fromFields == null)
{
return;
}
if (toFields == null)
{
return;
}
for (int f = 0; f < fromFields.Length; f++)
{
fromField = (PropertyInfo)fromFields[f];
for (int t = 0; t < toFields.Length; t++)
{
toField = (PropertyInfo)toFields[t];
if (fromField.Name != toField.Name)
{
continue;
}
toField.SetValue(toRecord,
fromField.GetValue(fromRecord, null),
null);
break;
}
}
}
catch (Exception)
{
throw;
}
}
#endregion
#region Set Properties
public static void SetProperties(PropertyInfo[] fromFields,
object fromRecord,
object toRecord)
{
PropertyInfo fromField = null;
try
{
if (fromFields == null)
{
return;
}
for (int f = 0; f < fromFields.Length; f++)
{
fromField = (PropertyInfo)fromFields[f];
fromField.SetValue(toRecord,
fromField.GetValue(fromRecord, null),
null);
}
}
catch (Exception)
{
throw;
}
}
#endregion
}
}
|
|
| PropertyHandler Sample For Identical Classes | |
MyClass record = new MyClass(); MyClass newRecord = new MyClass(); PropertyInfo[] fromFields = null; fromFields = typeof(MyClass).GetProperties(); PropertyHandler.SetProperties(fromFields, record, newRecord); |
|
| PropertyHandler Sample For Similar Classes | |
MyClass record = new MyClass(); MyOtherClass newRecord = new MyOtherClass(); PropertyInfo[] fromFields = null; PropertyInfo[] toFields = null; fromFields = typeof(MyClass).GetProperties(); toFields = typeof(MyOtherClass).GetProperties(); PropertyHandler.SetProperties(fromFields,toFields,record, newRecord); |
|
| Self Validation Methods | |
// Some of the code below relies on runtime reflection. Certain aspects
// of reflection are detrimental to performance. Where possible, you
// can create static instances of the reflection results. It will give
// the power without the overhead of using reflection.
// Here is a sample business class layer self validation method.
private bool ValidateSave(CellAlignment record)
{
object[,] properties = null;
List<string> returnMessages = new List<string>();
try
{
// Use the .GetFields() method mentioned later in this sample.
properties = this.GetFields(this.GetType());
if (!record.ValidateRequiredProperties(properties,
returnMessages))
{
for (int i = 0; i < returnMessages.Count; i++)
{
Debug.WriteLine(returnMessages[i]);
}
return false;
}
}
catch (Exception) { throw;}
return true;
}
// This code was extracted from the ADO.NET Code Generator mentioned
// above.
// Here is a sample property to demonstrate how to use the
// ColumnAttributes class. It sets this as being required
// and tells the validator that it is an int data type.
private int cellAlignmentID = 0;
[ColumnAttributes("CellAlignmentID",true,"int")]
public int CellAlignmentID
{
get
{
return cellAlignmentID;
}
set
{
if (value != cellAlignmentID)
{
cellAlignmentID = valuue;
}
}
}
// The ColumnAttributes class itself.
[AttributeUsage(AttributeTargets.Property,AllowMultiple = true)]
public sealed class ColumnAttributes : System.Attribute
{
private string columnName;
private bool isRequired;
private string propertyType;
public string ColumnName
{
get { return columnName; }
}
public bool IsRequired
{
get { return isRequired; }
}
public string PropertyType
{
get { return propertyType; }
}
public ColumnAttributes(string columnNameValue,
bool isRequiredValue,
string propertyTypeValue)
{
columnName = columnNameValue;
isRequired = isRequiredValue;
propertyType = propertyTypeValue;
}
}
// Here is a method we can use to get an array of
// PropertyInfo objects as well as custom attributes.
// Make sure every class has this in method available
// to run on itself. The ADO.NET Code Generator has
// this apart of the CustomAttributes.cs that all
// DataObjects inherit.
public object[,] GetFields(Type t)
{
PropertyInfo[] fields = t.GetProperties();
PropertyInfo field;
Attribute[] attributes;
object[,] structureInfo = new object[fields.Length,2];
try
{
for(int i =0;i<fields.Length;i++)
{
field = fields[i];
attributes = Attribute.GetCustomAttributes(field,
typeof(DataObjects.Tables.ColumnAttributes),
false);
structureInfo[i,0] = field;
structureInfo[i,1] = attributes;
}
}
catch (Exception) { throw; }
return structureInfo;
}
public bool ValidateRequiredProperties(object[,] properties,
List<string> returnMessages)
{
bool returnValue = true;
PropertyInfo property;
Attribute[] attributes;
ColumnAttributes columnAttribute = null;
try
{
if (properties == null)
{
throw new Exception("Please pass in the results of this.GetFields().");
}
if (returnMessages != null)
{
returnMessages.Clear();
}
for (int i = 0; i <= properties.GetUpperBound(0); i++)
{
property = (PropertyInfo)properties[i, 0];
attributes = (Attribute[])properties[i, 1];
foreach (Attribute attribute in attributes)
{
columnAttribute = (ColumnAttributes)attribute;
if (!columnAttribute.IsRequired)
{
continue;
}
// Debug.WriteLine(columnAttribute.ColumnName);
// Debug.WriteLine(property.GetValue(this,null));
if (!this.ValidateRequiredPropertyInfo(columnAttribute,
property))
{
returnValue = false;
if (returnMessages != null)
{
returnMessages.Add(columnAttribute.ColumnName + " is required.");
}
}
}
}
}
catch (Exception) { throw;}
return returnValue;
}
public bool ValidateRequiredProperties(object[,] properties)
{
List<string> returnMessages = null;
try
{
return ValidateRequiredProperties(properties,
returnMessages);
}
catch (Exception) { throw; }
}
public bool ValidateRequiredPropertyInfo(ColumnAttributes columnAttribute,
PropertyInfo property)
{
try
{
switch (columnAttribute.PropertyType.ToLower())
{
case "int":
if ((int)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "int16":
if ((Int16)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "int32":
if ((Int32)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "int64":
if ((Int64)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "uint":
if ((uint)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "uint16":
if ((UInt16)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "uint32":
if ((UInt32)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "uint64":
if ((UInt64)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "double":
if ((double)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "float":
if ((float)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "single":
if ((Single)property.GetValue(this,
null) == 0)
{
return false;
}
break;
case "string":
if ((string)property.GetValue(this,
null) == String.Empty)
{
return false;
}
break;
case "guid":
if ((Guid)property.GetValue(this,
null) == Guid.Empty)
{
return false;
}
break;
default:
if (property.GetValue(this,
null) == null)
{
return false;
}
break;
}
}
catch (Exception) { throw; }
return true;
}
|
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作者：灵动生活 郝宪玮
出处：http://www.cnblogs.com/ywqu
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