Nhibernate: read list of strings
I know I can read a list of strings like below using nhibernate
HasMany(x => x.Attachments)
.KeyColumn("RowId")
.Table("PostTable").Element("PostKey");
But this creates an additional table, is there a way for example. UserType or whatever so that we can write to the list directly ... if so, any example of custom UserType using nhibernate? with sample code ...
I also want the If to add the value to the list, which should also be stored. I saw below example code that breaks if we add a value to the list ...
private virtual string StringValue
public virtual IList<string> valueList
{
get { return StringValue; }
set { StringValue = string.Join(value, "|"); }
}
+2
source to share
1 answer
You can do it with IUserType, for example:
public class DelimitedList : IUserType
{
private const string delimiter = "|";
public new bool Equals(object x, object y)
{
return object.Equals(x, y);
}
public int GetHashCode(object x)
{
return x.GetHashCode();
}
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
var r = rs[names[0]];
return r == DBNull.Value
? new List<string>()
: ((string)r).SplitAndTrim(new [] { delimiter });
}
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
object paramVal = DBNull.Value;
if (value != null)
{
paramVal = ((IEnumerable<string>)value).Join(delimiter);
}
var parameter = (IDataParameter)cmd.Parameters[index];
parameter.Value = paramVal;
}
public object DeepCopy(object value)
{
return value;
}
public object Replace(object original, object target, object owner)
{
return original;
}
public object Assemble(object cached, object owner)
{
return cached;
}
public object Disassemble(object value)
{
return value;
}
public SqlType[] SqlTypes
{
get { return new SqlType[] { new StringSqlType() }; }
}
public Type ReturnedType
{
get { return typeof(IList<string>); }
}
public bool IsMutable
{
get { return false; }
}
}
Then define the IList <string> property type = "MyApp.DelimitedList, MyApp".
NOTE. SplitAndTrim is a string extension with various overrides that I created. Here's the main method:
public static IList<string> SplitAndTrim(this string s, StringSplitOptions options, params string[] delimiters)
{
if (s == null)
{
return null;
}
var query = s.Split(delimiters, StringSplitOptions.None).Select(x => x.Trim());
if (options == StringSplitOptions.RemoveEmptyEntries)
{
query = query.Where(x => x.Trim() != string.Empty);
}
return query.ToList();
}
+1
source to share