public static Func <T, T> GenerateSelectedColumns <T> (string[] Fields = null)
{
string[] EntityFields;
if (Fields == null)
{
EntityFields = typeof(T).GetProperties()
.Where(d => d.GetGetMethod().IsStatic == false)
.Select(propertyInfo => propertyInfo.Name)
.ToArray();
}
else
{
EntityFields = Fields;
}
var xParameter = Expression.Parameter(typeof(T), "o");
var xNew = Expression.New(typeof(T));
var bindings = EntityFields.Select(o => o.Trim())
.Select(o => {
var mi = typeof(T).GetProperty(o);
var xOriginal = Expression.Property(xParameter, mi);
return(Expression.Bind(mi, xOriginal));
});
var xInit = Expression.MemberInit(xNew, bindings);
var lambda = Expression.Lambda <Func <T, T> > (xInit, xParameter);
return(lambda.Compile());
}
public static Func <T, T> DynamicSelectGenerator <T>(string Fields = "")
{
string[] EntityFields;
if (Fields == "")
{
EntityFields = typeof(T).GetProperties().Select(propertyInfo => propertyInfo.Name).ToArray();
}
else
{
EntityFields = Fields.Split(',');
}
var xParameter = Expression.Parameter(typeof(T), "o");
var xNew = Expression.New(typeof(T));
var bindings = EntityFields.Select(o => o.Trim())
.Select(o =>
{
var mi = typeof(T).GetProperty(o);
var xOriginal = Expression.Property(xParameter, mi);
return(Expression.Bind(mi, xOriginal));
}
);
var xInit = Expression.MemberInit(xNew, bindings);
var lambda = Expression.Lambda <Func <T, T> >(xInit, xParameter);
return(lambda.Compile());
}
public static Func <T, T> DynamicSelectGenerator <T>(string Fields = "")
{
string[] EntityFields;
if (Fields == "")
{
// get Properties of the T
EntityFields = typeof(T).GetProperties().Select(propertyInfo => propertyInfo.Name).ToArray();
}
else
{
EntityFields = Fields.Split(',');
}
// input parameter "o"
var xParameter = Expression.Parameter(typeof(T), "o");
// new statement "new Data()"
var xNew = Expression.New(typeof(T));
// create initializers
var bindings = EntityFields.Select(o => o.Trim())
.Select(o =>
{
// property "Field1"
var mi = typeof(T).GetProperty(o);
// original value "o.Field1"
var xOriginal = Expression.Property(xParameter, mi);
// set value "Field1 = o.Field1"
return(Expression.Bind(mi, xOriginal));
}
);
// initialization "new Data { Field1 = o.Field1, Field2 = o.Field2 }"
var xInit = Expression.MemberInit(xNew, bindings);
// expression "o => new Data { Field1 = o.Field1, Field2 = o.Field2 }"
var lambda = Expression.Lambda <Func <T, T> >(xInit, xParameter);
// compile to Func<Data, Data>
return(lambda.Compile());
}