TryGetOriginalValue Method

Overview

The TryGetOriginalValue method allows you to get the baseline (original) value for the specified column from the row’s original-values snapshot, if such a snapshot exists. Original values are captured automatically when an Unchanged row is modified for the first time or when the Delete method is called.

The method returns true when a snapshot exists and contains the specified column; otherwise it returns false and outputs null.

Namespace and Assembly

Namespace: PocoDataSet.Data
Assembly: PocoDataSet.Data.dll

Usage Example

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

// 2. Create an empty data table
IDataTable departmentDataTable = dataSet.AddNewTable("Department");
departmentDataTable.AddColumn("Id", DataTypeNames.INT32);
departmentDataTable.AddColumn("Name", DataTypeNames.STRING);

// 3. Create a new row by AddNewRow method on data table, the row state is Added
IDataRow departmentDataRow = departmentDataTable.AddNewRow();
departmentDataRow["Name"] = "Emergency";

// 4. Call the AcceptChanges method to set row state into Unchanged
departmentDataRow.AcceptChanges();

// 5. Try to read the original value before any modification or deletion. // No snapshot exists yet, so the method returns false.
object? departmentName = null;
departmentDataRow.TryGetOriginalValue("Name", out departmentName);

// 6. Call Delete method to put row into Deleted state
departmentDataRow.Delete();

// 7. Call TryGetOriginalValue method to get cached "Emergency" value for the Name column
bool hasOriginalName = departmentDataRow.TryGetOriginalValue("Name", out departmentName);

 

Table of Content POCO DataSet API References POCO DataSet Types DataRow Members

 

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Business Process Programming in .Net
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