This way
C#
public Form1()
{
InitializeComponent();
ReportDocument doc = new ReportDocument();
doc.Load("C:\\Users\\Mudassar\\CrystalReport_SetTextBoxValue_CS\\CrystalReport1.rpt");
crystalReportViewer1.ReportSource = doc;
crystalReportViewer1.Refresh();
TextObject txtObject = (TextObject)doc.ReportDefinition.Sections["Section1"].ReportObjects["Text1"];
txtObject.Text = "This is a test.";
}
VB.Net
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Dim doc As New ReportDocument()
doc.Load("C:\Users\Mudassar\Desktop\Dropbox\Samples\Windows\CrystalReport_SetTextBoxValue_CS\CrystalReport_SetTextBoxValue_VB\CrystalReport1.rpt")
CrystalReportViewer1.ReportSource = doc
CrystalReportViewer1.Refresh()
Dim txtObject As TextObject = DirectCast(doc.ReportDefinition.Sections("Section1").ReportObjects("Text1"), TextObject)
txtObject.Text = "This is a test."
End Sub