Fields

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A Field is a placeholder used to insert text and graphics into a document.

A field code includes the following elements:

Field Name
The field name. Refer to the following article for a list of all available fields: Field Codes.
Property
Instruction or variable used in a field. This is an optional element.
Switch
An optional parameter that allows you to modify a field result. A switch starts with a backslash followed by a switch argument. A field can have its own set of switches that specify the field’s behavior. You can also use format switches to define formats for numeric, text, date, and time fields. Refer to the following section for a list of supported format switches: Format Switches.

Field Code Structure

A field in the document consists of two ranges—CodeRange and ResultRange. Use the Field.Range property to obtain the total range the field occupies.

Supported Field Types

Non-MailMerge

Regular fields used to insert simple data (for example, DATE, TIME, or PAGE). The Non-MailMerge field results are shown after the update.

MailMerge

Fields used in the mail merge process. You should bind a document to a data source to obtain MailMerge field values. Execute mail merge to evaluate MailMerge field values and display them in the document.

Mixed

Fields that do not require a data source to obtain their values (INCLUDEPICTURE, CREATEDATE, and DOCVARIABLE). They are substituted with the resulting values during mail merge.

Formula

The = (Formula) field is a code that uses mathematical formulas and numeric field values to calculate a number. The formula field syntax:

{={NUMERIC FIELD} Operator {NUMERIC FIELD}}

The Word Processing Document API supports the following operators in the formula field:

  • Addition (+)
  • Subtraction (-)
  • Multiplication (*)
  • Division (/)
  • Powers and Roots (^)
  • Equal to (=)
  • Less than (<)
  • Less than or equal to (<=)
  • Greater than (>)
  • Greater than or equal to (>=)
  • Not equal to (<>)

You can change the field’s numeric format. Refer to the following topic for a list of available numeric format switches: Numeric Format Switch.

Insert and Modify Fields

Fields are stored in the FieldCollection collection. The SubDocument.Fields property allows you to access the field collection. Call the FieldCollection.Create method to insert a new field. You can add fields to any SubDocument—the main document body, headers, footers, text boxes, comments, footnotes, and endnotes. Use the following API to access the content of these document parts:

Document part Member
Main document body SubDocument.BeginUpdateSubDocument.EndUpdate
Header Section.BeginUpdateHeaderSection.EndUpdateHeader
Footer Section.BeginUpdateFooterSection.EndUpdateFooter
Comment Comment.BeginUpdateComment.EndUpdate
Footnote and Endnote Note.BeginUpdateNote.EndUpdate
Text Box TextBox.Document

Example: Create a Field

The code snippet below uses the SYMBOL field to add a check mark (✔) to the document:

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Access a document.
    Document document = wordProcessor.Document;

    // Start to edit the document.
    document.BeginUpdate();

    // Create the "SYMBOL" field.
    document.Fields.Create(document.Range.Start, "SYMBOL 252 \\f Wingdings \\s 28");

    // Finalize to edit the document.
    document.EndUpdate();

    // Update all fields in the main document body.
    document.Fields.Update();

    // Save the document to the file.
    document.SaveDocument("Result.docx", DocumentFormat.OpenXml);
}

Example: Create a Field from a Range

The code sample below inserts text and converts it to the SYMBOL field.

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;

//...
using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    Document document = wordProcessor.Document;

    // Start to edit the document.
    document.BeginUpdate();

    // Append text.
    document.AppendText("SYMBOL 0x54 \\f Wingdings \\s 24");

    // Convert inserted text to a field.
    document.Fields.Create(document.Paragraphs[0].Range);

    // Update all fields.
    document.Fields.Update();

    // Finalize to edit the document.
    document.EndUpdate();

    // Save the result
    document.SaveDocument("Result.docx", DocumentFormat.OpenXml);
}

Example: Modify a Field

The following code snippet specifies a custom date and time format for all DATE fields in the document:

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Access a document.
    Document document = wordProcessor.Document;
    // ...
    // Check all fields in the document.
    for (int i = 0; i < document.Fields.Count; i++)
    {
        // Access a field code.
        string fieldCode = document.GetText(document.Fields[i].CodeRange);
        // Check whether a field code is "DATE".
        if (fieldCode == "DATE")
        {
            // Set the document position to the end of the field code range.
            DocumentPosition position = document.Fields[i].CodeRange.End;
            // Specify a date and time format for the field. 
            document.InsertText(position, @" \@ ""M/d/yyyy HH:mm:ss""");
        }
    }
    // Update all fields in the main document body.
    document.Fields.Update();
}

Update Fields

Most fields are updated automatically when the document is saved or printed, or during the mail merge operation. Use the following methods to update document fields on demand:

Method Description
Field.Update Updates a field.
FieldCollection.Update Updates all fields in specific parts of the document (main body, text box, header, footer, comment, footnote, and endnote).
Document.UpdateAllFields Updates all fields in the document.

The code sample below updates all fields in the document:

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Access a document.
    Document document = wordProcessor.Document;
    //...
    // Update all fields in the document.
    document.UpdateAllFields();
}

If the field’s Field.Locked property is true, this field is not updated. You can set the FieldOptions.UpdateLockedFields option to UpdateLockedFields.Always to update locked fields.

Update DOCVARIABLE Fields

Use the FieldOptions.UpdateDocVariablesBeforePrint and FieldOptions.UpdateDocVariablesBeforeCopy field options to specify whether to update the DOCVARIABLE field before the document is printed or before the field is copied. When the DOCVARIABLE field is updated, the RichEditDocumentServer.CalculateDocumentVariable event fires. Handle this event to analyze DOCVARIABLE field switches and arguments, and specify how to calculate a field result.

The RichEditDocumentServer.CalculateDocumentVariable event does not occur for a locked DOCVARIABLE field, and the field value remains unchanged. Set the FieldOptions.UpdateLockedFields option to the UpdateLockedFields.DocVariableOnly value to update locked DOCVARIABLE fields.

Tip

Refer to the following GitHub examples for more information on how to use the DOCVARIABLE fields:

Suppress Field Updates for Loaded Documents

The Word Processing Document API updates all document fields when it loads a document. You can cancel the DATE, TIME, and DOCVARIABLE field updates. Handle the RichEditDocumentServer.BeforeImport event and define the UpdateFieldOptions options within the event handler to specify whether to update these fields.

The following example demonstrates how to cancel the update of the DATE, TIME, and DOCVARIABLE document fields for all document formats:

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.Import;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Handle the BeforeImport event.
    wordProcessor.BeforeImport += WordProcessor_BeforeImport;

    // Load a document from the file.
    wordProcessor.LoadDocument("FirstLook.docx");
}

private static void WordProcessor_BeforeImport(object sender, BeforeImportEventArgs e)
{

    // Cancel the DATE, TIME, and DOCVARIABLE fields' update.
    UpdateFieldOptions updateFieldOptions = ((DocumentImporterOptions)e.Options).UpdateField;
    updateFieldOptions.Date = false;
    updateFieldOptions.Time = false;
    updateFieldOptions.DocVariable = false;
}  

Replace Fields with Field Values

You can unlink a field to convert the field result to text or graphics. Unlinked fields cannot be updated. Use the following methods to unlink document fields:

Method Description
Field.Unlink Replaces the field with the field value.
FieldCollection.Unlink Replaces all fields with their values in a specific document part (main body, header, footer, comment, text box, footnote, or endnote).
Document.UnlinkAllFields Replaces all document fields with field values.

The following example unlinks all fields in text boxes:

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Access a document.
    Document document = wordProcessor.Document;

    // Check all shapes in the document.
    foreach (Shape shape in document.Shapes)
    {
        // Check whether the shape is a text box.
        if (shape.ShapeFormat.HasText)
        {
            // Access text box content.
            SubDocument textBoxDocument = shape.ShapeFormat.TextBox.Document;
            //...
            // Unlink all fields in the text box.
            textBoxDocument.Fields.Unlink();
        }
    }
}

Show Field Codes

Use the Field.ShowCodes property to display field codes for specific fields instead of field results.

The code snippet below displays field codes for all fields in the main document body:

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Access a document.
    Document document = wordProcessor.Document;

    // Load a document from the file.
    document.LoadDocument("MailMergeSimple.docx", DocumentFormat.OpenXml);

    // Check all fields in the main document body.
    for (int i = 0; i < document.Fields.Count; i++)
    {
        // Show field codes.
        document.Fields[i].ShowCodes = true;
    }
}

Specify Field Options

Use the RichEditDocumentServer.Options.Fields property to specify field options. These options define the appearance and behavior of the document fields.

The code snippet below demonstrates how to specify field options.

Specify Field Options

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Specify field options.
    FieldOptions fieldOptions = wordProcessor.Options.Fields;
    fieldOptions.HighlightMode = FieldsHighlightMode.Always;
    fieldOptions.HighlightColor = System.Drawing.Color.LightSalmon;
    fieldOptions.UseCurrentCultureDateTimeFormat = true;
    fieldOptions.ThrowExceptionOnInvalidFormatSwitch = true;
    fieldOptions.UpdateFieldsInTextBoxes = true;

    // Access a document.
    Document document = wordProcessor.Document;

    // Insert a text box in the document.
    Shape myTextBox = document.Shapes.InsertTextBox(document.Range.Start);

    // Access text box content.
    SubDocument textBoxDocument1 = myTextBox.ShapeFormat.TextBox.Document;

    // Create the "DATE" field.
    textBoxDocument.Fields.Create(textBoxDocument.Range.Start, "DATE");

    // Update the field.
    textBoxDocument.Fields.Update();
}

Remove Fields

Call the SubDocument.Delete method and pass the field range to remove the field from the document.

The following example removes all fields from the document:

using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
//...

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
{
    // Access a document.
    Document document = wordProcessor.Document;
    //...
    // Remove all fields from the collection
    for (int i = document.Fields.Count-1; i >= 0; i--) 
    {
        document.Delete(document.Fields[i].Range); 
    }
}
See Also