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    <p>My best guess is that some part of your code is just really slow.</p> <p>The event only fires for each visible cell in the grid. If you attempt to debug the event, focus will shift to the debugger, and when you return to the application the cells need to be redrawn, causing the event to fire again, thus giving the <em>impression</em> that the event fires continuously. It does not, however.</p> <p>Here are some pointers to improve performance:</p> <ul> <li>You are constructing a new <code>DivaDs</code> every time the event fires <ul> <li>Instead, consider reusing the same instance of the class as a member variable</li> <li>What happens in the constructor?</li> </ul></li> <li>Take a closer look at the <code>GetBackColor</code> method or <code>ColorTranslator.FromHtml</code> and see if any modifications can be made to improve performance.</li> </ul> <p><strong>Update</strong></p> <p>It appears you are querying the database for each cell in the grid. This is a really bad idea.</p> <p>A simple solution would be to preload all ActionTypes and their background colors (or at least the subset of ActionTypes that is displayed in the grid) before setting the grid's data source.</p> <pre><code>// member variable private Dictionary&lt;byte, Color&gt; actionTypeColorDict; void BuildActionTypeColorDictionary() { string connectionString = ConfigurationManager .ConnectionStrings[DivaSqlSiteConnString].ConnectionString; using (SqlConnection conn = new SqlConnection(connectionString)) using (SqlCommand cmd = conn.CreateCommand()) using (SqlDataAdapter adapter = new SqlDataAdapter(cmd)) { // load all action type IDs and corresponding background color: cmd.CommandText = @"SELECT ActionTypeID, BackColor FROM ActionTypes"; DataTable actionTypeTable = new DataTable(); adapter.Fill(actionTypeTable); // build a dictionary consisting of action type IDs // and their corresponding colors actionTypeColorDict = actionTypeTable.AsEnumerable().ToDictionary( r =&gt; r.Field&lt;byte&gt;("ActionTypeID"), r =&gt; ColorTranslator.FromHtml(r.Field&lt;string&gt;("ColorCode"))); } } </code></pre> <p>Call the <code>BuildActionTypeColorDictionary</code> method before setting the data source of the grid. In the <code>RowStyle</code> or <code>CustomDrawCell</code> events, use the new dictionary member to determine the background color. See the following modified version of your <code>RowStyle</code> code:</p> <pre><code>private void gvStep_RowStyle(object sender,DevExpress.XtraGrid.Views.Grid.RowStyleEventArgs e) { try { DataRow row = gvStep.GetDataRow(e.RowHandle); if (row == null) return; byte actionTypeID = row.Field&lt;byte&gt;("ActionImage"); // look up color in the dictionary: e.Appearance.BackColor = actionTypeColorDict[actionTypeID]; } catch (Exception ex) { XtraMessageBox.Show(ex.Message); } } </code></pre>
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    1. COyes you are right. I should use same instance. However, this is not the only problem. I want to stop event when gridview painted and seen by the user because there is no need to use this event after gridview shown
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    2. COI made some modifications on my code to increase speed of my code but it is still slower than it used to. I just changed the backcolor of the rows. if this event not firing continuously, there should be another reason why it is slower. I updated my code you may check out
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    3. CO@cihata87, you are making a round trip to Sql to determine the background color. This is the likely cause of the slow down. I'd suggest caching the action type to background color mapping in your app to speed things up.
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