Provide Custom Names to the Field List Items

• Dec 14, 2023
• 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 item names in the Field List. It applies to the Visual Studio Report Designer and the End-User Report Designer for WinForms.

To customize the Field List, assign a custom data source that implements the IDisplayNameProvider interface to the report. This interface has two methods - the GetDataSourceDisplayName() method returns the new data source name, and the GetFieldDisplayName method returns the new field name. Note that the Field List does not show fields for which the GetFieldDisplayName method returns null or Empty.

The following image shows the original Field List (on the left) and the customized Field List (on the right):

MySqlDataSource.cs

using System;
using DevExpress.Data;
using DevExpress.DataAccess.Sql;
// ...

    public class MySqlDataSource : SqlDataSource, IDisplayNameProvider
    {
        public MySqlDataSource() {
        }

        public MySqlDataSource(SqlDataSource copyFrom) {
            this.LoadFromXml(copyFrom.SaveToXml());
        }

        // ...
        string IDisplayNameProvider.GetDataSourceDisplayName() {
            // Replace the default datasource display name
            // with a custom name.
            return "Northwind Traders";
        }

        string IDisplayNameProvider.GetFieldDisplayName(string[] fieldAccessors) {
            // Get the field name from the data member 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 
            // from the 'CategoriesProducts' relation only.
            if (fieldAccessors[0].StartsWith("Products")) {
                return null;
            }

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

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

MySqlDataSource.vb

Imports System
Imports DevExpress.Data
Imports DevExpress.DataAccess.Sql
' ...

    Public Class MySqlDataSource
        Inherits SqlDataSource
        Implements IDisplayNameProvider

        Public Sub New()
        End Sub

        Public Sub New(ByVal copyFrom As SqlDataSource)
            Me.LoadFromXml(copyFrom.SaveToXml())
        End Sub

        ' ...
        Private Function IDisplayNameProvider_GetDataSourceDisplayName() As String Implements IDisplayNameProvider.GetDataSourceDisplayName
            ' Replace the default datasource display name
            ' with a custom name.
            Return "Northwind Traders"
        End Function

        Private Function IDisplayNameProvider_GetFieldDisplayName(ByVal fieldAccessors() As String) As String Implements IDisplayNameProvider.GetFieldDisplayName
            ' Get the field name from the data member 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 
            ' from the 'CategoriesProducts' relation only.
            If fieldAccessors(0).StartsWith("Products") Then
                Return Nothing
            End If

            ' Insert spaces between separate words in the 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 c As Char In name
                ' Check if a character is upper case.
                ' To avoid spaces between the letters of acronyms,
                ' check if the previous character is upper case.
                If Char.IsUpper(c) AndAlso isPrevLow Then
                    result &= " " & c
                Else
                    result &= c
                End If
                isPrevLow = Char.IsLower(c)
            Next c
            Return result
        End Function
        ' ...
    End Class