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Author: ritazakhodyaeva

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+# Dashboard for WinForms - How to aggregate data by string concatenation
+
+This example shows how to aggregate your data by string concatenation.
+
+## Files to look at
+<!-- default file list -->
+* [Form1.cs](./CS/Dashboard_StringConcatAggregate/Form1.cs) (VB: [Form1.vb](./VB/Dashboard_StringConcatAggregate/Form1.vb))
+* [StringConcatFunction.cs](./CS/Dashboard_StringConcatAggregate/StringConcatFunction.cs) (VB: [StringConcatFunction.vb](./VB/Dashboard_StringConcatAggregate/StringConcatFunction.vb))
+<!-- default file list end -->
+
+## Overview
+
+In this example, the [Grid](https://docs.devexpress.com/Dashboard/15150/winforms-dashboard/winforms-designer/create-dashboards-in-the-winforms-designer/dashboard-item-settings/grid) dashboard item displays _СontactName_ values concatenated by country. 
+
+
+The following expressions aggregates data by string concatenation for _СontactName_ values:
+
+| Calculated Field | Expression |
+| --- | --- |
+| Contact names by countries | ``` StringConcat([ContactName]) ``` |
+
+Call the [CriteriaOperator.RegisterCustomFunction](https://docs.devexpress.com/CoreLibraries/DevExpress.Data.Filtering.CriteriaOperator.RegisterCustomFunction(DevExpress.Data.Filtering.ICustomFunctionOperator)) method to register a custom function in your project. The following code snippet shows how to register the numeric group interval's function: 
+
+[Program.cs](./CS/Dashboard_StringConcatAggregatel/Program.cs):
+```csharp
+using System;
+using System.Windows.Forms
+using DevExpress.Data.Filtering;
+
+namespace Dashboard_StringConcatAggregate {
+ static class Program {
+ /// <summary>
+ /// The main entry point for the application.
+ /// </summary>
+ [STAThread]
+ static void Main() {
+ // ...
+ CriteriaOperator.RegisterCustomFunction(new StringConcatFunction());
+ Application.Run(new Form1()); 
+ }
+ }
+}
+```
+[Program.vb](./VB/Dashboard_StringConcatAggregate/Program.vb):
+```vb
+Imports System.Windows.Forms using DevExpress.Data.Filtering
+
+Namespace Dashboard_StringConcatAggregate
+Friend Module Program
+''' <summary>
+''' The main entry point for the application.
+''' </summary>
+<STAThread>
+Sub Main()
+' ...
+CriteriaOperator.RegisterCustomFunction(New StringConcatFunction())
+Application.Run(New Form1())
+End Sub
+End Module
+End Namespace
+
+```
+
+## Documentation
+
+- [Expression Constants, Operators, and Functions](https://docs.devexpress.com/Dashboard/400122/common-features/advanced-analytics/expression-constants-operators-and-functions)
+- [Grouping](https://docs.devexpress.com/Dashboard/116535/common-features/data-shaping/grouping)
+- [ICustomFunctionOperatorBrowsable](https://docs.devexpress.com/CoreLibraries/DevExpress.Data.Filtering.ICustomFunctionOperatorBrowsable)
+- [ICustomFunctionOperatorFormattable](https://docs.devexpress.com/CoreLibraries/DevExpress.Data.Filtering.ICustomFunctionOperatorFormattable)
+
+## More Examples
+
+- [Dashboard for WinForms - How to Calculate the Numeric Group Interval](https://github.com/DevExpress-Examples/winforms-dashboard-numeric-group-intervals)
+- [Dashboard for WinForms - How to Calculate Fiscal Functions from Date-Time Data Fields](https://github.com/DevExpress-Examples/How-to-calculate-fiscal-functions-for-date-time-data-fields)