/// <summary>
/// 获取实体对象中对应的数据库列的值。
/// </summary>
/// <typeparam name="TEntity">实体对象类型</typeparam>
/// <param name="metaColumn">列的元数据</param>
/// <param name="entity">实体对象</param>
/// <returns>实体对象中对应的数据库列的值</returns>
private static object GetColumnValue <TEntity>(MetaDataColumn metaColumn, TEntity entity)
{
object value = metaColumn.Member.GetValue(entity, null);
//如果当前列的数据类型可设置为空类型且值为null
return((IsNullableType(metaColumn.DataType) && value == null) ? DBNull.Value : value);
}
private Dictionary<string, MetaDataColumn> GetColumns(Type entityType)
{
PropertyInfo[] properties = entityType.GetProperties();
if (properties == null)
return this._columns;
this._columns = new Dictionary<string, MetaDataColumn>(properties.Length);
foreach (PropertyInfo property in properties)
{
var attr = Attribute.GetCustomAttribute(property, typeof(ColumnAttribute)) as ColumnAttribute;
if (attr == null) continue;
var metacolumn = new MetaDataColumn(property, attr);
this._columns.Add(metacolumn.Name.ToLower(), metacolumn);
}
return this._columns;
}
/// <summary>
/// 获取实体对象。
/// </summary>
/// <typeparam name="TEntity">实体对象类型</typeparam>
/// <param name="dr">DbDataReader</param>
/// <param name="entity">实体对象</param>
/// <param name="metaDataTable">MetaDataTable对象</param>
/// <returns>实体对象</returns>
public static TEntity GetEntity <TEntity>(DbDataReader dr, TEntity entity, MetaDataTable metaDataTable)
{
for (int i = 0; i < dr.FieldCount; i++)
{
string colName = dr.GetName(i).ToLower();
if (!metaDataTable.Columns.ContainsKey(colName))
{
continue;
}
MetaDataColumn metaColumn = metaDataTable.Columns[colName];
if (!dr.IsDBNull(i))
{
object value = Convert.ChangeType(dr.GetValue(i),
IsNullableType(metaColumn.DataType) ?
metaColumn.DataType.GetGenericArguments()[0] : metaColumn.DataType);
metaColumn.Member.SetValue(entity, value, null);
}
}
return(entity);
}
private Dictionary <string, MetaDataColumn> GetColumns(Type entityType)
{
PropertyInfo[] properties = entityType.GetProperties();
if (properties == null)
{
return(this._columns);
}
this._columns = new Dictionary <string, MetaDataColumn>(properties.Length);
foreach (PropertyInfo property in properties)
{
var attr = Attribute.GetCustomAttribute(property, typeof(ColumnAttribute)) as ColumnAttribute;
if (attr == null)
{
continue;
}
var metacolumn = new MetaDataColumn(property, attr);
this._columns.Add(metacolumn.Name.ToLower(), metacolumn);
}
return(this._columns);
}
private static bool IsIgnored(MetaDataColumn metaColumn)
{
return(metaColumn.Attribute.IsIgnored || metaColumn.Attribute.IsIdentity);
}
