DwColumnAttribute Class

.NET Standard 2.x

Specifies the column data information.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Inheritance Constructor

System.Attribute

Syntax

    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
    public class DwColumnAttribute : SqlColumnAttribute

Constructors

Name	Description
DwColumnAttribute(string column)	Initializes a new instance of the DwColumnAttribute class.
DwColumnAttribute(string tableAlias, string column)	Initializes a new instance of the DwColumnAttribute class.
DwColumnAttribute(string tableAlias, string column, string columnAlias)	Initializes a new instance of the DwColumnAttribute class.

Properties

Name	Return Type	Description
Column	string	Gets the name of the column the property is mapped to.
ColumnAlias	string	Gets the alias of the column the property is mapped to.
Order	int	Gets or sets the zero-based order of the column the property is mapped to.
TableAlias	string	Gets the alias of the table where the column belongs to.
TypeName	string	Gets or sets the data type of the column the property is mapped to.
Validation	string	Gets or sets the validation rule for the column.
ValidationMsg	string	Gets or sets the validation message.

Remarks

Corresponding to the column defined by DataWindow.

DwColumnAttribute has a few overriding constructors which allow table alias and column alias to be passed in.

Examples

The following code example enables the column placeholder @(COLUMNS_PLACEHOLDER) in the DwSelect attribute of Model, which means the SQL statement to be generated when data is retrieved will use the column name placeholder @(COLUMN_PLACEHOLDER) to replace all column names in DwSelect.

Model: D_Department

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_department", DwStyle.Grid)]
    [Table("Department", Schema = "dbo")]
    #region DwSelectAttribute  
    [DwSelect("PBSELECT( VERSION(400) TABLE(NAME=\"Department\" ) @(_COLUMNS_PLACEHOLDER_) )")]
    #endregion
    [UpdateWhereStrategy(UpdateWhereStrategy.KeyAndConcurrencyCheckColumns)]
    [DwKeyModificationStrategy(UpdateSqlStrategy.DeleteThenInsert)]
    [DwTemplate(DataFormat.Xml, "xml_default", "Templates\\xml_setparameter_default.xml", IsDefault = true)]
    public class D_Department
    {
        [Key]
        [DwColumn("Department", "DepartmentID")]
        public int Departmentid { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Department", "Name")]
        public string Name { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Department", "Budget")]
        public decimal Budget { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Department", "StartDate")]
        public DateTime Startdate { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Department", "Administrator")]
        public int? Administrator { get; set; }

    }

}

Example Method:

using System;
using DWNet.Data;

namespace Appeon.ApiDoc.DwColumnAttributeExamples
{
    public class DwColumnAttributeExample
    {
        private readonly SchoolContext _context;

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

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

            // Retrieves rows from the database for datastore
            datastore.Retrieve();

            /*The following SQL is generated:
            
            SELECT
            [Department].[DepartmentID],
            [Department].[Name],
            [Department].[Budget],
            [Department].[StartDate],
            [Department].[Administrator] 
            FROM [Department]
            */
        }
    }
}

Example Refer To

DataWindow File: d_department