Formatting Unique and Duplicate Values

• Aug 27, 2019
• 3 minutes to read

The Unique-Duplicate conditional format allows you to format cells whose values are unique or duplicate.

The image below shows the grid column whose City cells are green if their values are unique.

This topic consists of the following sections:

• Adding Rules in Code
• Adding Rules Using Conditional Formatting Menu
• Adding Rules Using Conditional Formatting Rules Manager

Adding Rules in Code

Create the UniqueDuplicateRuleFormatCondition class instance and specify the following settings to create a conditional format in code:

• Specify the comparison logic by setting the UniqueDuplicateRuleFormatCondition.Rule property.
• Use the FormatConditionBase.FieldName property to specify the column’s field name to which to apply the conditional format.

• Specify the target cells’ formatting:

  • Use the FormatConditionBase.PredefinedFormatName property to specify the predefined format, or
  • Set the custom format using the ExpressionConditionBase.Format property.
• Set a selective expression using the UniqueDuplicateRuleFormatCondition.SelectiveExpression property if it is necessary to select data records to which the rule should be applied.
• Add the resulting UniqueDuplicateRuleFormatCondition instance to the TableView.FormatConditions (or TreeListView.FormatConditions) collection.

The following code sample illustrates how to define a conditional format in markup:

XAML

<dxg:TableView.FormatConditions>
   <dxg:UniqueDuplicateRuleFormatCondition Rule="Unique" FieldName="City" PredefinedFormatName="GreenFillWithDarkGreenText" />
</dxg:TableView.FormatConditions>

The code sample below illustrates how to define the same conditional format in code-behind:

C#

var cityFormatCondition = new UniqueDuplicateRuleFormatCondition() {
   ValueRule = UniqueDuplicateRuleFormatCondition.Unique,
   FieldName = "City",
   PredefinedFormatName = "GreenFillWithDarkGreenText"
};
view.FormatConditions.Add(cityFormatCondition);

VB.NET

Dim cityFormatCondition = New UniqueDuplicateRuleFormatCondition() With {
   .ValueRule = UniqueDuplicateRuleFormatCondition.Unique,
   .FieldName = "City",
   .PredefinedFormatName = "GreenFillWithDarkGreenText"
}
view.FormatConditions.Add(cityFormatCondition)

Adding Rules Using Conditional Formatting Menu

1. Select the Highlight Cells Rules item in the Conditional Formatting Menu, and choose the Duplicate Values in the invoked sub menu.
2. Specify the conditional format (Unique or Duplicate) in the invoked window dialog.
3. Choose a format to define the applied rule’s visual appearance. The conditional formatting menu allows you to use only predefined formats stored within the TableView.PredefinedFormats (or TreeListView.PredefinedFormats) collection.
4. Enable the apply format to the entire row option to apply a conditional format to the entire row, if necessary.

Adding Rules Using Conditional Formatting Rules Manager

1. Click the New Rule… in the Conditional Formatting Rules Manager.
2. Select the Format only unique or duplicate values rule type in the invoked New Formatting Rule window dialog.
3. Choose the conditional format (Unique or Duplicate).
4. To define the visual appearance of the applied rule, click the Format button, and specify the required settings in the invoked Format Cells dialog window. See the Format Cells Dialog Window section of the Conditional Formatting Rules Manager topic to learn more.