DwChildAttribute Class

.NET Standard 2.x

Specifies the data source.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Inheritance Constructor

System.Attribute

Syntax

    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
    public class DwChildAttribute : Attribute

Constructors

Name	Description
DwChildAttribute(string dataColumn, string displayColumn, Type modelType)	Initializes a new instance of the DwChildAttribute class.

Properties

Name	Return Type	Description
AutoRerieve	bool	Whether to automatically retrieve data.
DataColumn	string	The data column.
DisplayColumn	string	The display data column name.
ModelType	Type	The model type for data source.

Remarks

Corresponding to the DDDW of DataWindow.

AutoRerieve is optional. The default value is false. It can be set to true when the child model has no retrieval arguments.

Examples

The following code example demonstrates how to use the Model DwChild attribute, and use GetChild to get this child DataWindow.

Model: D_Course

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using SnapObjects.Data;
using DWNet.Data;
using Newtonsoft.Json;

namespace Appeon.ApiDoc.Models
{
    [DataWindow("d_course", DwStyle.Grid)]
    [Table("Course", Schema = "dbo")]
    #region DwSelectAttribute  
    [DwSelect("PBSELECT( VERSION(400) TABLE(NAME=\"Course\" ) @(_COLUMNS_PLACEHOLDER_) )")]
    #endregion
    [UpdateWhereStrategy(UpdateWhereStrategy.KeyAndConcurrencyCheckColumns)]
    [DwKeyModificationStrategy(UpdateSqlStrategy.DeleteThenInsert)]
    public class D_Course
    {
        [Key]
        [DwColumn("Course", "CourseID")]
        public int Courseid { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Course", "Title")]
        public string Title { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Course", "Credits")]
        public int Credits { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Course", "DepartmentID")]
        [DwChild("Departmentid", "Name", typeof(Dddw_Department), AutoRetrieve = true)]
        public int Departmentid { get; set; }

    }

}

Example Method:

using System;
using DWNet.Data;

namespace Appeon.ApiDoc.DwChildAttributeExamples
{
    public class DwChildAttributeExample
    {
        private readonly SchoolContext _context;

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

        public void Example()
        {
            var datastore = new DataStore("d_course", _context);
            datastore.Retrieve();
			
			//Gets the child DataWindow.
            var child = datastore.GetChild("Departmentid");

            // Shows the total number of rows in the child DataWindow.
            Console.WriteLine($"child RowCount={child.RowCount}.");

            /* This code example produces the following output:
            
            child RowCount=5.
            */
        }
    }
}

Example Refer To

DataWindow File: d_course