LINQ Count rows in dataset with conditions

Yeah..thanks but I tried that and here's the frustrating response from vs...

Error      2      'System.Data.EnumerableRowCollection<QADCManager.QADCMainDatabase.terrain_type_vs_unit_type_detailsRow>' does not contain a definition for 'Count' and no extension method 'Count' accepting a first argument of type 'System.Data.EnumerableRowCollection<QADCManager.QADCMainDatabase.terrain_type_vs_unit_type_detailsRow>' could be found (are you missing a using directive or an assembly reference?)      


That's why I'm stuck here....

can you post the definition for qADCMainDatabase.terrain_type_vs_unit_type_details

       [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
        [global::System.ComponentModel.Browsable(false)]
        [global::System.ComponentModel.DesignerSerializationVisibility(global::System.ComponentModel.DesignerSerializationVisibility.Content)]
        public terrain_type_vs_unit_type_detailsDataTable terrain_type_vs_unit_type_details {
            get {
                return this.tableterrain_type_vs_unit_type_details;
            }
        }

As you can see it's a designer-created table, (I originally created the table in SQL Server).

Here's the internal partial class def

  /// <summary>
        ///Represents the strongly named DataTable class.
        ///</summary>
        [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Data.Design.TypedDataSetGenerator", "2.0.0.0")]
        [global::System.Serializable()]
        [global::System.Xml.Serialization.XmlSchemaProviderAttribute("GetTypedTableSchema")]
        public partial class terrain_type_vs_unit_type_detailsDataTable : global::System.Data.TypedTableBase<terrain_type_vs_unit_type_detailsRow> {
           
            private global::System.Data.DataColumn columnsection_name;
           
            private global::System.Data.DataColumn columnterrain_type_name;
           
            private global::System.Data.DataColumn columnunit_type_name;
           
            private global::System.Data.DataColumn columnaction_points_to_enter_tile;
           
            private global::System.Data.DataColumn columnoverall_attack_modifier;
           
            private global::System.Data.DataColumn columnoverall_defense_modifier;
            .
.
.

okay, if I understand you correctly and terrain_type_vs_unit_type_details is a LINQ-to-SQL table/object you don't need the .AsEnumerable()

so you're query would be:

var recordCount = (from c in qADCMainDatabase.terrain_typ_vs_unit_type_details
                             where c.terrain_type_name == terrainType
                             where c.section_name == sectionName
                             where c.unit_type_name == unitTypeName
                             select c).Count();

Although you're right that it does not need AsEnumerable() cast it's still treating "c" as a row no the table.  I can't use the Count() member at the end (same error message).  

Perhaps I need to use a the equiv of sql's select count(*) from... but I don't know th LINQ equivalent .

I'm not sure why it wouldn't work the way I posted it, unless I'm misunderstanding what's behind the objects.  I've done it the following way many times:

var qRows = from c in qADCMainDatabase.terrain_typ_vs_unit_type_details
                      where c.terrain_type_name == terrainType
                      where c.section_name == sectionName
                      where c.unit_type_name == unitTypeName
                      select c;

var rowCount = qRows.Count();

qRows becomes an IENumerable of type terrain_typ_vs_unit_type_details

can you post the code where you create the instance to the datacontext?

I just dropped a new dataset on a visual form and named it aADCMainDatabase..like I would do with any strongly typed dataset in C#.  

One thing to note, I load the data (hydrate?) in the dataset via an XML file, not an SQL query.


Interestingly, this line of code works...but it seems messy to cast the results into a container in this manner...

                    var records = (from c in qADCMainDatabase.terrain_type_vs_unit_type_details
                                   where c.terrain_type_name == terrainType
                                   where c.section_name == sectionName
                                   where c.unit_type_name == unitTypeName
                                    select c).AsDataView<QADCMainDatabase.terrain_type_vs_unit_type_detailsRow>().Count;

why the dataset?  why not use LINQ directly against the XML?

Because I load in the XML all at once into my dataset.  My dataset is also driving a bunch of visual controls (like grids, etc..).

The XML is only touched by the dataset to load/save state to a persistent source.

Although that exact solution will not work, it got me *a* solution that did work.

Hi...Revisiting this question because I have figured out the correct way of doing this and wanted folks to see the more LINQ correct way of things:

int RecordCount = qADCMainDatabase.terrain_type_vs_unit_type_details.AsEnumerable.Count(c => ((c.terrain_type_name == terrainType) & (c.section_name == sectionName) & (c.unit_type_name == unitTypeName)));

The FROM clause was not necessary and was throwing us all off.