public object Value { get; set; }

Public Property Value As Object

using System.Drawing;
using DevExpress.XtraReports.UI;
// ...
using DevExpress.XtraReports.Parameters;
// ...
using DevExpress.XtraReports.Expressions;
// ...
// Create a date report parameter.
// Use an expression to specify the parameter's default value.
var dateParameter = new Parameter() {
    Name = "date",
    Description = "Date:",
    Type = typeof(System.DateTime),
    ExpressionBindings = { new BasicExpressionBinding("Value", "Now()") }
};

// Create a label and bind the label's Text property to the parameter value.
// Use the parameter's name to reference the parameter in the label's expression.
var dateLabel = new XRLabel() {
    ExpressionBindings = { new ExpressionBinding("Text", "?date") },
    BoundsF = new RectangleF(0, 0, 200, 50),
};

// Create a report and add the label to the report's Detail band.
var report = new XtraReport() {
    Bands = { new DetailBand() { Controls = { dateLabel } } },
};

// Add the parameter to the report's Parameters collection.
report.Parameters.Add(dateParameter);

Imports DevExpress.XtraReports.UI
' ...
Imports DevExpress.XtraReports.Parameters
' ...
Imports DevExpress.XtraReports.Expressions
' ...
' Create a date report parameter.
' Use an expression to specify the parameter's default value.
Dim dateParameter = New Parameter() With {
    .Name = "date",
    .Description = "Date:",
    .Type = GetType(Date)
}

dateParameter.ExpressionBindings.Add(New BasicExpressionBinding("Value", "Now()"))

' Create a label and bind the label's Text property to the parameter value.
' Use the parameter's name to reference the parameter in the label's expression.
Dim dateLabel = New XRLabel() With {.BoundsF = New RectangleF(0, 0, 200, 50)}

dateLabel.ExpressionBindings.Add(New ExpressionBinding("Text", "?date"))

' Create a report and add the label to the report's Detail band.
Dim report = New XtraReport()
Dim band = New DetailBand()
band.Controls.Add(dateLabel)
report.Bands.Add(band)

' Add the parameter to the report's Parameters collection.
report.Parameters.Add(dateParameter)
'

EmployeeReport report = sender as EmployeeReport;
int year = Convert.ToInt32(report.Parameters["paramYear"].Value);
int month = Convert.ToInt32(report.Parameters["paramMonth"].Value);

ChildReport childReport = new ChildReport();
childReport.Parameters["Level"].Value = this.Parameters["Level"].Value;
childReport.DataSource = parentNode.Children;

if(startDateParameter != null || endDateParameter != null || startDateParameter.Type == typeof(DateTime) || endDateParameter.Type == typeof(DateTime)) {
    var startDate = (DateTime)startDateParameter.Value;
    var endDate = (DateTime)endDateParameter.Value;

DetailReport detailReport = new DetailReport();
detailReport.Parameters["catId"].Value = row["CategoryID"];
detailReport.Parameters["catName"].Value = row["CategoryName"];

// Specify default lookup values.
    this.Parameters["ReportColumns"].Value = new string[] { "ID", "Name", "Category", "Supplier", "UnitPrice" };
}

Dim report As EmployeeReport = TryCast(sender, EmployeeReport)
Dim year As Integer = Convert.ToInt32(report.Parameters("paramYear").Value)
Dim month As Integer = Convert.ToInt32(report.Parameters("paramMonth").Value)

Dim childReport As ChildReport = New ChildReport()
childReport.Parameters("Level").Value = Parameters("Level").Value
childReport.DataSource = parentNode.Children

Dim detailReport As DetailReport = New DetailReport()
detailReport.Parameters("catId").Value = row("CategoryID")
detailReport.Parameters("catName").Value = row("CategoryName")

' Specify default lookup values.
    Me.Parameters("ReportColumns").Value = New String() { "ID", "Name", "Category", "Supplier", "UnitPrice" }
End Sub

'INSTANT VB NOTE: The variable startDate was renamed since Visual Basic does not handle local variables named the same as class members well:
        Dim startDate_Renamed = CDate(StartDate.Value)
'INSTANT VB NOTE: The variable endDate was renamed since Visual Basic does not handle local variables named the same as class members well: