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dapper 自定义数据库字段和代码中Model字段不一致时候的mapping方法
namespace YourNamespace{ /// <summary> /// Uses the Name value of the ColumnAttribute specified, otherwise maps as usual. /// </summary> /// <typeparam name="T">The type of the object that this mapper applies to.</typeparam> public class ColumnAttributeTypeMapper<T> : FallbackTypeMapper { public ColumnAttributeTypeMapper() : base(new SqlMapper.ITypeMap[] { new CustomPropertyTypeMap( typeof(T), (type, columnName) => type.GetProperties().FirstOrDefault(prop => prop.GetCustomAttributes(false) .OfType<ColumnMappingAttribute>() .Any(attr => attr.Name == columnName) ) ), new DefaultTypeMap(typeof(T)) }) { } } [AttributeUsage(AttributeTargets.Property, AllowMultiple = true)] public class ColumnMappingAttribute : Attribute { public string Name { get; set; } } public class FallbackTypeMapper : SqlMapper.ITypeMap { private readonly IEnumerable<SqlMapper.ITypeMap> _mappers; public FallbackTypeMapper(IEnumerable<SqlMapper.ITypeMap> mappers) { _mappers = mappers; } public ConstructorInfo FindConstructor(string[] names, Type[] types) { foreach (var mapper in _mappers) { try { ConstructorInfo result = mapper.FindConstructor(names, types); if (result != null) { return result; } } catch (NotImplementedException) { } } return null; } public SqlMapper.IMemberMap GetConstructorParameter(ConstructorInfo constructor, string columnName) { foreach (var mapper in _mappers) { try { var result = mapper.GetConstructorParameter(constructor, columnName); if (result != null) { return result; } } catch (NotImplementedException) { } } return null; } public SqlMapper.IMemberMap GetMember(string columnName) { foreach (var mapper in _mappers) { try { var result = mapper.GetMember(columnName); if (result != null) { return result; } } catch (NotImplementedException) { } } return null; } } }
public static IEnumerable LoadWithCustomMapping(){ using (var conn = OpenDBConnection()) { Dapper.SqlMapper.SetTypeMap(typeof(MyArea), new ColumnAttributeTypeMapper()); return conn.Query("SELECT TOP 10 CAID,CAName,En FROM CityArea"); }}
dapper 自定义数据库字段和代码中Model字段不一致时候的mapping方法
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