RichEditDocumentServer.CalculateDocumentVariable Event
Fires when the DOCVARIABLE field is updated.
Namespace: DevExpress.XtraRichEdit
Assembly: DevExpress.RichEdit.v23.2.Core.dll
NuGet Packages: DevExpress.RichEdit.Core, DevExpress.Win.Navigation
Declaration
Event Data
The CalculateDocumentVariable event's data class is CalculateDocumentVariableEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| Arguments | Provides access to a collection of arguments within the DOCVARIABLE field. |
| FieldLocked | Gets or sets a locked attribute to the field for which the event occurs. |
| Handled | Gets or sets whether the default action is required. |
| KeepLastParagraph | Gets or sets whether the last paragraph of the inserted document is kept in the resulting document. |
| PreserveInsertedContentFormatting | Gets or sets whether to insert an additional hidden paragraph so that the inserted content is not formatted with the DOCVARIABLE field’s paragraph formatting. |
| Value | Gets or sets the value of the DOCVARIABLE field that fired the event. |
| VariableName | Gets the name of the document variable to which the DOCVARIABLE field refers. |
Remarks
The CalculateDocumentVariable event fires when one of the following operations with a DOCVARIABLE field occurs:
- The field is updated after the Field.Update method call
- The field is updated after the FieldCollection.Update method call
- During the mail merge on the RichEditControl.MailMerge method call.
Handle this event to analyze DOCVARIABLE field switches and arguments, and specify custom content to insert into this field.
Assign a DocVariableValue.Current value to the CalculateDocumentVariableEventArgs.Value property and set e.Handled to true to retain the existing DOCVARIABLE value.
Locked DOCVARIABLE Fields
You can specify the FieldOptions.UpdateLockedFields property to raise the event for locked DOCVARIABLE fields.
Use the CalculateDocumentVariableEventArgs.FieldLocked property to lock/unlock the field in the CalculateDocumentVariable handler. Set e.Handled to true to apply changes.
Nested DOCVARIABLE Fields
If you use the RichEditDocumentServer.MailMerge method to evaluate nested DOCVARIABLE fields, set the RichEditMailMergeOptions.ViewMergedData option to true. Otherwise, you get field placeholders instead of values in the CalculateDocumentVariable handler.
Check the field’s CalculateDocumentVariableEventArgs.Arguments value to retrieve a nested field value. When the CalculateDocumentVariable event is fired for the first time, e.Arguments contains the <<FieldName_1>> (the placeholder for the field), because the merge field has not yet been calculated. In this case, do nothing in the event handler (use comparison and return statements if required).
Note
If you use the MailMerge method overload with a document parameter, handle the CalculateDocumentVariable event of a SubDocument passed as a parameter instead of the RichEditDocumentServer.CalculateDocumentVariable event.
Examples
How to: Handle the Event to Calculate a Field Value
The code sample below demonstrates how to handle the event to calculate the DOCVARIABLE field value. In this example, this field should insert a number of years the employee worked at a company. The nested MERGEFIELD refers to the HireDate entry in the database.
private static void WordProcessor_CalculateDocumentVariable(object sender, CalculateDocumentVariableEventArgs e)
{
if (e.Arguments.Count > 0)
{
// Retrieve the MERGEFIELD field value
DateTimeOffset hireDate = Convert.ToDateTime(e.Arguments[0].Value);
DateTimeOffset currentDate = DateTime.Now;
// Calculate the difference between the current date
// and the hire date
var dif = currentDate.Subtract(hireDate);
// Calculate the number of years
int years = dif.Days / 365;
// Specify the DOCVARIABLE field value
e.Value = years.ToString();
e.Handled = true;
}
e.Handled = true;
}
How to: Handle the Event to Insert Dynamic Content
This code snippet demonstrates how to handle the Document.CalculateDocumentVariable event to insert dynamic content into the document. In this example, it is used to get weather conditions. A variable name specified in the DOCVARIABLE indicates a choice between location and weather, while the location itself is specified by the field argument.
private static void Document_CalculateDocumentVariable(object sender, CalculateDocumentVariableEventArgs e) {
if (e.Arguments.Count > 0) {
string location = e.Arguments[0].Value.ToString();
if ((location.Trim() == String.Empty) || (location.Contains("<"))) {
e.Value = " ";
e.Handled = true;
return;
}
switch (e.VariableName) {
case "Weather":
Conditions conditions = new Conditions();
conditions = Weather.GetCurrentConditions(location);
e.Value = String.Format("Weather for {0}: \nConditions: {1}\nTemperature (C) :{2}\nHumidity: {3}\nWind: {4}\n",
location, conditions.Condition, conditions.TempC, conditions.Humidity, conditions.Wind);
break;
case "LOCATION":
if (location == "DO NOT CHANGE!") e.Value = DocVariableValue.Current;
break;
default:
e.Value = "LOCKED FIELD UPDATED";
break;
}
}
else {
e.Value = "LOCKED FIELD UPDATED";
}
e.Handled = true;
}
How to: Handle the Event to Insert Document Elements
The code sample below shows how to handle the RichEditDocumentServer.CalculateDocumentVariable event to insert a barcode and a table:
using (var wordProcessor = new RichEditDocumentServer()) {
wordProcessor.CreateNewDocument();
Document document = wordProcessor.Document;
// Create fields for a barcode and a table:
document.Fields.Create(document.Range.End, "DOCVARIABLE QRCODE");
document.Paragraphs.Append();
document.Fields.Create(document.Range.End, "DOCVARIABLE TABLE");
wordProcessor.CalculateDocumentVariable += WordProcessor_CalculateDocumentVariable;
// Update all document fields:
document.UpdateAllFields();
// Save the result:
wordProcessor.SaveDocument("result.docx", DocumentFormat.OpenXml);
}
void WordProcessor_CalculateDocumentVariable(object sender, CalculateDocumentVariableEventArgs e) {
switch (e.VariableName) {
case "QRCODE":
// Create new RichEditDocumentServer instance:
var doc = new RichEditDocumentServer();
// Insert a barcode as a shape
Shape picture = doc.Document.Shapes.InsertPicture(doc.Document.Range.End, GenerateQrCode());
picture.TextWrapping = TextWrappingType.InLineWithText;
// Set the field value to the RichEditDocumentServer instance:
e.Value = doc;
e.Handled = true;
break;
case "TABLE":
// Create new RichEditDocumentServer instance:
var doc1 = new RichEditDocumentServer();
// Insert a table:
GenerateTable(doc1.Document);
// Set the field value to the RichEditDocumentServer instance:
e.Value = doc1;
e.Handled = true;
break;
}
}
// This method generates a barcode:
static Bitmap GenerateQrCode() {
BarCode barCode = new BarCode();
barCode.Symbology = Symbology.QRCode;
barCode.CodeText = "https://www.devexpress.com/";
barCode.BackColor = Color.White;
barCode.ForeColor = Color.Black;
barCode.RotationAngle = 0;
barCode.CodeBinaryData = Encoding.Default.GetBytes(barCode.CodeText);
barCode.Options.QRCode.CompactionMode = QRCodeCompactionMode.Byte;
barCode.Options.QRCode.ErrorLevel = QRCodeErrorLevel.Q;
barCode.Options.QRCode.ShowCodeText = false;
barCode.DpiX = 72;
barCode.DpiY = 72;
barCode.Module = 2f;
return barCode.BarCodeImage;
}
// This method generates a table:
static Table GenerateTable(Document document) {
Table table = document.Tables.Create(document.Range.Start, 3,3);
document.InsertSingleLineText(table.Rows[0].Cells[1].Range.Start, "Active Customers");
document.InsertSingleLineText(table[1, 0].Range.Start, "Photo");
document.InsertSingleLineText(table[1, 1].Range.Start, "Customer Info");
document.InsertSingleLineText(table[1, 2].Range.Start, "Rentals");
return table;
}
Related GitHub Examples
The following code snippets (auto-collected from DevExpress Examples) contain references to the CalculateDocumentVariable event.
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