DocVariableValue Class

A class which allows you to specify the current value of a DOCVARIABLE field in the Document.CalculateDocumentVariable event handler.

Namespace: DevExpress.XtraRichEdit

Assembly: DevExpress.RichEdit.v18.2.Core.dll

Declaration

C#

public class DocVariableValue

VB.NET

Public Class DocVariableValue

Remarks

When the Document.CalculateDocumentVariable event occurs, the current value of the DOCVARIABLE field is lost by default. You should explicitly specify the field value using the CalculateDocumentVariableEventArgs.Value property within the Document.CalculateDocumentVariable event handler.

To retain the current value of the field, set the DocVariableValue’s DocVariableValue.Current value to the CalculateDocumentVariableEventArgs.Value property.

Example

This code snippet demonstrates how to handle the RichEditControl.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 field indicates a choice between location and weather, while the location itself is specified by the field argument.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-use-document-variable-docvariable-fields-e3099

Form1.cs

void eventHandler_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;
}

Form1.vb

Private Sub eventHandler_CalculateDocumentVariable(ByVal sender As Object, ByVal e As CalculateDocumentVariableEventArgs) Handles richEditControl1.CalculateDocumentVariable
    If e.Arguments.Count > 0 Then
        Dim location As String = e.Arguments(0).Value.ToString()
        If (location.Trim() = String.Empty) OrElse (location.Contains("<")) Then
            e.Value = " "
            e.Handled = True
            Return
        End If
        Select Case e.VariableName
            Case "Weather"
                Dim conditions As New Conditions()
                conditions = Weather.GetCurrentConditions(location)
                e.Value = String.Format("Weather for {0}: " & vbLf & "Conditions: {1}" & vbLf & "Temperature (C) :{2}" & vbLf & "Humidity: {3}" & vbLf & "Wind: {4}" & vbLf, location, conditions.Condition, conditions.TempC, conditions.Humidity, conditions.Wind)
            Case "LOCATION"
                If location = "DO NOT CHANGE!" Then
                    e.Value = DocVariableValue.Current
                End If
            Case Else
                e.Value = "LOCKED FIELD UPDATED"
        End Select
    Else
        e.Value = "LOCKED FIELD UPDATED"
    End If
    e.Handled = True
End Sub

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the DocVariableValue class.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

how-to-use-document-variable-docvariable-fields-e3099/CS/DocumentVariablesExample/Form1.cs#L89

case "LOCATION":
    if (location == "DO NOT CHANGE!") e.Value = DocVariableValue.Current;
    break;

VB.NET

how-to-use-document-variable-docvariable-fields-e3099/VB/DocumentVariablesExample/Form1.vb#L88

If location = "DO NOT CHANGE!" Then
    e.Value = DocVariableValue.Current
End If

Inheritance

Object

DocVariableValue