AsInterface Method

Overview

The AsInterface method creates a live proxy for an IDataRow that implements a POCO interface (TInterface). Getting and setting properties on the returned interface reads and updates the underlying data row fields.

This enables the "programming to interfaces" approach: application code can work with strongly-typed POCO interfaces while still storing values inside a schema-driven, dynamic data set.

Declaration

/// <summary>
/// Gets "live" data row as an interface
/// </summary>
/// <typeparam name="TInterface">POCO interface type</typeparam>
/// <param name="dataRow">Data row</param>
/// <returns>"Live" data row as an interface</returns>
public static TInterface AsInterface<TInterface>(this IDataRow? dataRow) where TInterface : class

/// <summary>
/// Gets "live" data row as an interface
/// </summary>
/// <typeparam name="TInterface">POCO interface type</typeparam>
/// <param name="dataRow">Data row</param>
/// <param name="nameMap">Name map</param>
/// <returns>"Live" data row as an interface</returns>
public static TInterface AsInterface<TInterface>(this IDataRow? dataRow, IDictionary<string, string> nameMap) where TInterface : class

Namespace and Assembly

Namespace: PocoDataSet.Extensions
Assembly: PocoDataSet.Extensions.dll

Usage Example

Assume you have a POCO interface that describes an employment type:

internal interface IEmploymentType
{
  int Id { get; set; }
  string Code { get; set; }
  string? Description { get; set; }
}

Create a table, populate a row, then access the row through the interface:

// 1. Create an empty data set
IDataSet dataSet = DataSetFactory.CreateDataSet();

// 2. Create an empty table from the POCO interface
IDataTable employmentTypeDataTable = dataSet.AddNewTableFromPocoInterface("EmploymentType", typeof(IEmploymentType));

// 3. Create a new row and set values
IDataRow employmentTypeDataRow = employmentTypeDataTable.AddNewRow();
employmentTypeDataRow["Id"] = 1;
employmentTypeDataRow["Code"] = "ET01";
employmentTypeDataRow["Description"] = "Full Time";

// 4. Get a live proxy that implements IEmploymentType
IEmploymentType employmentType = employmentTypeDataRow.AsInterface<IEmploymentType>();

// 5. Change a property via the interface
employmentType.Code = "ET02";

// 6. Verify the underlying row has changed
string? updatedCode = employmentTypeDataRow["Code"] as string;

If your interface property names do not match column names, provide a name map:

// 1. Create an empty data set
IDataSet dataSet = DataSetFactory.CreateDataSet();

// 2. Create EmploymentType table
IDataTable employmentTypeDataTable = dataSet.AddNewTable("EmploymentType");
employmentTypeDataTable.AddColumn("EmploymentTypeId", DataTypeNames.INT32);
employmentTypeDataTable.AddColumn("EmploymentTypeCode", DataTypeNames.STRING);
employmentTypeDataTable.AddColumn("EmploymentTypeDescription", DataTypeNames.STRING);

// 3. Create a new row and set values
IDataRow employmentTypeDataRow = employmentTypeDataTable.AddNewRow();
employmentTypeDataRow["EmploymentTypeId"] = 1;
employmentTypeDataRow["EmploymentTypeCode"] = "ET01";
employmentTypeDataRow["EmploymentTypeDescription"] = "Full Time";

// 4. Create name map to map interface properties to data row field names
IDictionary<string, string> nameMap = new Dictionary<string, string>();
nameMap.Add("Id", "EmploymentTypeId");
nameMap.Add("Code", "EmploymentTypeCode");
nameMap.Add("Description", "EmploymentTypeDescription");

// 5. Get a live proxy that implements IEmploymentType
IEmploymentType employmentType = employmentTypeDataRow.AsInterface<IEmploymentType>(nameMap);

// 5. Change a property via the interface
employmentType.Code = "ET02";

// 6. Verify the underlying row has changed
string? updatedCode = employmentTypeDataRow["EmploymentTypeCode"] as string;

 

Table of Content POCO DataSet DataRow Members

 

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Business Process Programming in .Net
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