IDataStore.Avg<TModel>(Func<TModel, decimal> selector, Predicate<TModel> predicate) Method

.NET Standard 2.x

Computes the average of a sequence of decimal values. These values are obtained by invoking a transform function on each row in the primary buffer of the DataStore which has been filtered by a predicate.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Syntax

  public decimal Avg<TModel>(Func<TModel, decimal> selector, Predicate<TModel> predicate);

Type Parameters

TModel

The type of a model class that matches with the current DataObject.

Parameters

selector System.Func<TModel, decimal>

A transform function to apply to each row.

predicate System.Predicate<TModel>

A function to evaluate each row in the primary buffer for a condition.

Returns

System.decimal

The average of the sequence of values.

Examples

The following code example demonstrates how to use the Avg<TModel>(Func<TModel, decimal>, Predicate<TModel>) method to compute the average budget of all departments.

using Appeon.ApiDoc.Models;
using DWNet.Data;
using System;

namespace Appeon.ApiDoc.IDataStoreExamples
{
    public class AvgExample
    {
        private readonly SchoolContext _context;

        public AvgExample(SchoolContext dataContext)
        {
            // Sets the data context
            _context = dataContext;
        }

        public void Example2()
        {
            // Instantiates a DataStore object with datawindow: d_department.
            var datastore = new DataStore("d_department", _context);

            datastore.Retrieve();

            // This datastore has 4 records
            // but after filtered by Budget > 200000.00
            // values of Budget are:
            // 350000.00, 250000.00
            // so avg(Budget) is 300000.00
            decimal avg = datastore.Avg<D_Department>(
                o => o.Budget,
                o => o.Budget > 200000.00m);

            Console.WriteLine(
                "The Avg(Budget) for records " +
                "whose Budget is larger than 200000.00 is: {0}",
                avg);

            /*This code produces the following output:
            
            The Avg(Budget) for records whose Budget is larger than 200000.00 is: 
            300000.0000
            */
        }
    }
}

Example Refer To

Model Class: D_Department
DataWindow File: d_department

Applies to

.NET Standard

2.x