Hi I am trying to use LLBLGEN pro to write a new sql interface to my software. I want to be able to do dymanic queries.

That is create an entity and collection based on the table name (I have done this ok).

I then want to be able to do searches which the user may want to perform. I can see that Predicates seem to work at compile time, not runtime,

Any pointers where to start.

Thanks

That depends on how the user would input the search query. Here are some ideas:

Dynamic Linq. This is not directly supported by LLBLGen, but apparently some users have this working. http://www.llblgen.com/TinyForum/Messages.aspx?ThreadID=17046

Using switches. http://www.llblgen.com/TinyForum/Messages.aspx?ThreadID=1966

Using Activator class. http://www.llblgen.com/TinyForum/Messages.aspx?ThreadID=6304&StartAtMessage=0&#34915

daelmo wrote:

That depends on how the user would input the search query. Here are some ideas:

Dynamic Linq. This is not directly supported by LLBLGen, but apparently some users have this working. http://www.llblgen.com/TinyForum/Messages.aspx?ThreadID=17046

I'm no expert on Linq so might give this one a miss

Using switches. http://www.llblgen.com/TinyForum/Messages.aspx?ThreadID=1966

There are thousands of possible fields, that would be a mighty case statement

Using Activator class. http://www.llblgen.com/TinyForum/Messages.aspx?ThreadID=6304&StartAtMessage=0&#34915

Sounds like a plan. I use the Activator class already to create the Entity class as all I know is the table name.

Hi Thanks for the help. That all worked fine. My code now looks like the following

    // Create an Entity Class based on the Table Name
    public CommonEntityBase CreateEntity(String Table)
    {
        thisTable = char.ToUpper(Table[0]) + Table.Substring(1); //Make the first character uppercase
        String Name = String.Format("MicronetDAL.EntityClasses.{0}Entity", thisTable);

        Assembly a = Assembly.LoadFrom(".\\MicronetDAL.dll");
        thisEntityType = a.GetType(Name);

        TableEntity = (CommonEntityBase)Activator.CreateInstance(thisEntityType);
        return(TableEntity);
    }

    // Create a Entity Collection based on the Table name
    public EntityCollection GetEntityCollection()
    {
        object e;

        String Name = String.Format("MicronetDAL.FactoryClasses.{0}EntityFactory", thisTable);
        Assembly a = Assembly.LoadFrom(".\\MicronetDAL.dll");
        Type t = a.GetType(Name);

        e = (object)Activator.CreateInstance(t);
        return (new EntityCollection((IEntityFactory2)e));
    }

    String ConvertFieldName(String f)
    {
        String ret = char.ToUpper(f[0]) + f.Substring(1);
        return(ret);
    }

   bool FetchEntityCollection(DataAccessAdapter da, EntityCollection thisCollection, IRelationPredicateBucket filter, int max)
    {
        try
        {
            da.FetchEntityCollection(thisCollection, filter, max);
            if (thisCollection.Count == 0)
            {
                Diagnostic.ErrorCode = Error_Code.INOT_ERR;
                Diagnostic.LastError = "";
                return (false);
            }
            return (true);
        }
        catch (Exception ex)
        {
            Diagnostic.CatchError(ex, null,null);
            return (false);
        }

    }

    public bool SelectRecord(String table,  sqlSelectParam[] SelectArray)
    {
        bool ret = true;

        DataAccessAdapter da = new DataAccessAdapter();
        CommonEntityBase = CreateEntity(table);
        EntityCollection thisCollection = GetEntityCollection();

        try
        {
            IRelationPredicateBucket filter = new RelationPredicateBucket();
            for (int i = 0; i < SelectArray.Length; i++)
            {
                FieldCompareValuePredicate predicateToAdd = null;

                IEntityField2 f = TableEntity.Fields[ConvertFieldName(SelectArray[i].FieldName)];
                predicateToAdd = new FieldCompareValuePredicate(f, null, ComparisonOperator.Equal, SelectArray[i].value);

                if (predicateToAdd != null)
                {
                    if (i == 0)
                        filter.PredicateExpression.Add(predicateToAdd);
                    else
                        filter.PredicateExpression.AddWithAnd(predicateToAdd);
                }
            }

            ret = this.FetchEntityCollection(da,thisCollection, filter, 0);
        }
        catch (Exception ex)
        {
            ret = false;
            Diagnostic.CatchError(ex, null, thisTable);
        }
        return (ret);
    }

Thanks for sharing.