MysqlHelper使用反射机制智能推算数据类型以及属性名称
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MysqlHelper使用反射机制智能推算数据类型以及属性名称
class MySqlHelper
{
private string ConnString;
public MySqlHelper( string connectionString)
{
ConnString = connectionString;
}
public IList<T> RunMySqlSelect4ReturnList<T>( string strCommand) where T : new ()
{
MySqlCommand mySqlCommand = new MySqlCommand();
mySqlCommand.CommandText = strCommand.ToString();
IList <PropertyInfo> ilPropertyInfo = typeof (T).GetProperties().ToList(); // p[0].Name =travel_id;
IList<T> ilResult = new List<T> ();
DataTable dt = new DataTable();
using (MySqlConnection conn = new MySqlConnection( this .ConnString))
{
conn.Open();
using (MySqlCommand cmd = mySqlCommand)
{
cmd.Connection = conn;
using (MySqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.SequentialAccess))
{
dt.Load(rdr);
}
}
}
foreach (DataRow dr in dt.Rows)
{
T tItem = new T();
foreach ( var v in ilPropertyInfo)
{
if (dt.Columns[v.Name] == null ) continue ;
ConvertionExtensions.SetValue(tItem, v.Name, dr[v.Name]);
}
ilResult.Add(tItem);
}
return ilResult;
}
public T getSinggleObj<T>( string strCommand) where T : new ()
{
MySqlCommand mySqlCommand = new MySqlCommand();
mySqlCommand.CommandText = strCommand.ToString();
IList <PropertyInfo> ilPropertyInfo = typeof (T).GetProperties().ToList(); // p[0].Name =travel_id;
T ilResult = new T();
DataTable dt = new DataTable();
using (MySqlConnection conn = new MySqlConnection( this .ConnString))
{
conn.Open();
using (MySqlCommand cmd = mySqlCommand)
{
cmd.Connection = conn;
using (MySqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.SequentialAccess))
{
dt.Load(rdr);
}
}
}
if (dt.Rows.Count <= 0 )
{
return default (T);
}
else
{
foreach (DataRow dr in dt.Rows)
{
T tItem = new T();
foreach ( var v in ilPropertyInfo)
{
if (dt.Columns[v.Name] == null ) continue ;
ConvertionExtensions.SetValue(tItem, v.Name, dr[v.Name]);
}
ilResult = tItem;
}
}
return ilResult;
}
public IList<T> RunMySqlSelect4ReturnList<T>(DataTable dts) where T : new ()
{
IList <PropertyInfo> ilPropertyInfo = typeof (T).GetProperties().ToList(); // p[0].Name =travel_id;
IList<T> ilResult = new List<T> ();
DataTable dt = dts;
foreach (DataRow dr in dt.Rows)
{
T tItem = new T();
foreach ( var v in ilPropertyInfo)
{
if (dt.Columns[v.Name] == null ) continue ;
ConvertionExtensions.SetValue(tItem, v.Name, dr[v.Name]);
}
ilResult.Add(tItem);
}
return ilResult;
}
}
public static class ConvertionExtensions
{
public static T ConvertTo<T>( this IConvertible convertibleValue)
{
var t = typeof (T);
if ( null == convertibleValue)
{
return default (T);
}
if (! typeof (T).IsGenericType)
{
return (T)Convert.ChangeType(convertibleValue, typeof (T));
}
else
{
Type genericTypeDefinition = typeof (T).GetGenericTypeDefinition();
if (genericTypeDefinition == typeof (Nullable<> ))
{
return (T)Convert.ChangeType(convertibleValue, Nullable.GetUnderlyingType( typeof (T)));
}
}
throw new InvalidCastException( string .Format( " Invalid cast from type \"{0}\" to type \"{1}\". " , convertibleValue.GetType().FullName, typeof (T).FullName));
}
public static void SetValue( object inputObject, string propertyName, object propertyVal)
{
// find out the type
Type type = inputObject.GetType();
// get the property information based on the type
System.Reflection.PropertyInfo propertyInfo = type.GetProperty(propertyName);
// find the property type
Type propertyType = propertyInfo.PropertyType;
// Convert.ChangeType does not handle conversion to nullable types
// if the property type is nullable, we need to get the underlying type of the property
var targetType = IsNullableType(propertyInfo.PropertyType) ? Nullable.GetUnderlyingType(propertyInfo.PropertyType) : propertyInfo.PropertyType;
// Returns an System.Object with the specified System.Type and whose value is
// equivalent to the specified object.
propertyVal = Convert.ChangeType(propertyVal, targetType);
// Set the value of the property
propertyInfo.SetValue(inputObject, propertyVal, null );
}
private static bool IsNullableType(Type type)
{
return type.IsGenericType && type.GetGenericTypeDefinition().Equals( typeof (Nullable<> ));
}
}
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