Provide Custom Names to the Field List Items

• Aug 10, 2018
• 3 minutes to read

Tip

Online Example: How to provide custom names for the Field List data items

This example demonstrates how to change the names of items listed in the Field List (both in the Visual Studio Report Designer and End-User Report Designer for WinForms) by making the report’s data source (a DataSet object in this example) implement the IDisplayNameProvider interface.

When a localized field name contains the white space character, leave this white space when referring to this field (e.g. Categories.Categories Products.Discontinued).

When the IDisplayNameProvider.GetFieldDisplayName method returns null or Empty, the corresponding data item becomes hidden in the Field List.

The following image illustrates the look of a Field List before (left picture) and after (right picture) its customization:

MyDataSet.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DevExpress.Data;
// ...
class MyDataSet :nwindDataSet, IDisplayNameProvider {
// ...
    string IDisplayNameProvider.GetDataSourceDisplayName() {
        // Substitute the default datasource display name
        // with a custom one.
        return "Northwind Traders";
    }

    string IDisplayNameProvider.GetFieldDisplayName(string[] fieldAccessors) {
        // Get a field name form the data member's name. 
        string fieldName = fieldAccessors[fieldAccessors.Length - 1];

        // Hide the data member if its name ends with 'ID'.
        if(fieldName.EndsWith("ID")) {
            return null;
        }

        // Hide the 'Products' table, because its fields are accessible 
        // via the 'CategoriesProducts' table only.
        if(fieldAccessors[0].StartsWith("Products")) {
            return null;
        }

        // Insert spaces between separate words of a field name.
        return ChangeNames(fieldName);
    }
    public string ChangeNames(string name) {
        string result = string.Empty;
        bool isPrevLow = false;

        foreach(char symb in name) {
            // Check if a character is of upper case.
            // To avoid spaces inside abbreviations, 
            // check if the previous character is of upper case, too.
            if(Char.IsUpper(symb) && isPrevLow) {
                result += " " + symb;
            }
            else {
                result += symb;
            }
            isPrevLow = Char.IsLower(symb);
        }
        return result;
    }
// ...
}

MyDataSet.vb

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks
Imports DevExpress.Data
' ...
Friend Class MyDataSet
    Inherits nwindDataSet
    Implements IDisplayNameProvider
' ...
    Private Function GetDataSourceDisplayName() As String _
    Implements IDisplayNameProvider.GetDataSourceDisplayName
        ' Substitute the default datasource display name
        ' with a custom one.
        Return "Northwind Traders"
    End Function

    Private Function GetFieldDisplayName(ByVal fieldAccessors() As String) As String _
    Implements IDisplayNameProvider.GetFieldDisplayName
        ' Get a field name form the data member's name. 
        Dim fieldName As String = fieldAccessors(fieldAccessors.Length - 1)

        ' Hide the data member if its name ends with 'ID'.
        If fieldName.EndsWith("ID") Then
            Return Nothing
        End If

        ' Hide the 'Products' table, because its fields are accessible 
        ' via the 'CategoriesProducts' table only.
        If fieldAccessors(0).StartsWith("Products") Then
            Return Nothing
        End If

        ' Insert spaces between separate words of a field name.
        Return ChangeNames(fieldName)
    End Function
    Public Function ChangeNames(ByVal name As String) As String
        Dim result As String = String.Empty
        Dim isPrevLow As Boolean = False

        For Each symb As Char In name
            ' Check if a character is of upper case.
            ' To avoid spaces inside abbreviations, 
            ' check if the previous character is of upper case, too.
            If Char.IsUpper(symb) AndAlso isPrevLow Then
                result &= " " & symb
            Else
                result &= symb
            End If
            isPrevLow = Char.IsLower(symb)
        Next symb
        Return result
    End Function
' ...
End Class