Pass Value Directly to Crystal Report using code

//write these command on Button click event
{

ParamReport param=new ParamReport();//making the object of rpt file

parameterDiscreteValue.Value = TextBox1.Text;//

currentParameterValues.Add(parameterDiscreteValue);

ParameterFieldDefinitions parameterFieldDefinitions = param.DataDefinition.ParameterFields;//

ParameterFieldDefinition parameterFieldDefinition = parameterFieldDefinitions["sample"];
                                                                                           //parameter field name

parameterFieldDefinition.ApplyCurrentValues(currentParameterValues);

CrystalReportViewer1.ReportSource = param;