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PO.NET DataTables, Events and determining if a specific column value has changed
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  1. PO.NET DataTables, Events and determining if a specific column value has changed
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    copied!<p>I have a Table, called Table1, with 3 columns:</p> <p>1) id - An integer and the primary key</p> <p>2) Name - A string</p> <p>3) Flagged - A boolean</p> <p>In most cases any rows of Table1 will be have Flagged set to false. I'm interested in knowing when <em>any</em> row has a value set to true. For now, I've simply been using the query</p> <p>Table1.Select("Flagged = TRUE")</p> <p>However, I thought it may be possible to determine this using events. </p> <p>The code below with the DataColumnChangeEventHandler will give me a notification for any column changes. The Notification_ColumnChanged() method gets called three times since there are three lines in the method UpdateTable().</p> <p>I would prefer to only get a notification once and only if any rows in the Flagged column are modified and therefore I don't need to call a Select() method. I was wondering if this is possible? Perhaps DataViews and events based on those would be a better way to achieve this? I'm interested in any suggestions.</p> <p>Thanks.</p> <pre><code>using System; using System.Data; namespace ConsoleApplication1 { public class Program { private TestDataSet _testDataSet; public Program() { _testDataSet = new TestDataSet(); _testDataSet.Table1.AddTable1Row(1, "name1", false); _testDataSet.Table1.AddTable1Row(2, "name2", false); _testDataSet.Table1.AcceptChanges(); _testDataSet.Table1.ColumnChanged += new DataColumnChangeEventHandler(Notification_ColumnChanged); } private void Notification_ColumnChanged(object sender, DataColumnChangeEventArgs e) { Console.WriteLine("Notification_ColumnChanged"); } public void UpdateTable() { Console.WriteLine("Updating"); _testDataSet.Table1[0].Flagged = true; _testDataSet.Table1[1].Flagged = true; _testDataSet.Table1[1].Name = "name2"; } public static void Main(string[] args) { Program p = new Program(); p.UpdateTable(); } } } </code></pre>
 

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