DwParameterAttribute Class

.NET Standard 2.x

Specifies the parameters required by the query statement.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Inheritance Constructor

System.Attribute

Syntax

    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]
    public class DwParameterAttribute : SqlParameterAttribute

Constructors

Name	Description
DwParameterAttribute(string name, Type dataType)	Initializes a new instance of the DwParameterAttribute class.

Properties

Name	Return Type	Description
Name	string	The name of the parameter.
DataType	Type	The data type of the parameter.

Remarks

Corresponding to the parameters defined by the DataWindow.

The parameter can be referenced by its name in the select syntax for the other attributes in the model class. The format to make reference: :paramName.

Examples

The following code example demonstrates how to use the Model DwParameter attribute. If the DwParameter attribute is defined in the Model, which means the parameter will be used by the SQL statement, then the parameter must be passed in when retrieving data.

Model: D_Person_With_Parameter

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;
using System.Collections;

namespace Appeon.ApiDoc.Models
{
    [DataWindow("d_person_with_parameter", DwStyle.Grid)]
    [Table("Person")]
    #region DwSelectAttribute  
    [DwSelect("PBSELECT( VERSION(400) TABLE(NAME=\"Person\" ) @(_COLUMNS_PLACEHOLDER_) WHERE(    EXP1 =\"Person.Discriminator\"   OP =\"=\"    EXP2 =\":s_Discriminator\" ) ) ARG(NAME = \"s_Discriminator\" TYPE = string)")]
    #endregion
    [DwParameter("s_Discriminator", typeof(string))]
    [DwKeyModificationStrategy(UpdateSqlStrategy.DeleteThenInsert)]
    [UpdateWhereStrategy(UpdateWhereStrategy.KeyAndConcurrencyCheckColumns)]
    public class D_Person_With_Parameter
    {
        [Key]
        [Identity]
        [DwColumn("Person", "PersonID")]
        public int Personid { get; set; }

        [ConcurrencyCheck]
        [StringLength(50)]
        [DwColumn("Person", "LastName")]
        public string Lastname { get; set; }

        [ConcurrencyCheck]
        [StringLength(50)]
        [DwColumn("Person", "FirstName")]
        public string Firstname { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Person", "HireDate")]
        public DateTime? Hiredate { get; set; }

        [ConcurrencyCheck]
        [DwColumn("Person", "EnrollmentDate")]
        public DateTime? Enrollmentdate { get; set; }

        [ConcurrencyCheck]
        [StringLength(50)]
        [DwColumn("Person", "Discriminator")]
        public string Discriminator { get; set; }

    }

}

Example Method:

using System;
using DWNet.Data;

namespace Appeon.ApiDoc.DwParameterAttributeExamples
{
    public class DwParameterAttributeExample
    {
        private readonly SchoolContext _context;

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

        public void Example()
        {
            var datastore = new DataStore("d_person_with_parameter", _context);
            datastore.Retrieve("Student");

            /* The following Select SQL is generated:
            
            exec sp_executesql N'SELECT
            [Person].[PersonID],
            [Person].[LastName],
            [Person].[FirstName],
            [Person].[HireDate],
            [Person].[EnrollmentDate],
            [Person].[Discriminator] 
            FROM [Person] 
            WHERE ([Person].[Discriminator] = @s_Discriminator)',N'@s_Discriminator nvarchar(4000)',@s_Discriminator=N'Student'
            */
        }
    }
}

Example Refer To

DataWindow File: d_person_with_parameter