problem overriding connection string from web.config file

Question

hi all i want use my web.config file connectionstring to my crystal report.my code is given below. protected void Page_Load(object sender EventArgs e) { TextBox1.Text = Session[Selected].ToString(); TextBox2.Text = Session[ReportBy].ToString(); TextBox3.Text = Session[FromDate].ToString(); TextBox4.Text = Session[ToDate].ToString(); ReportDocument repDoc = new ReportDocument(); string MyconnectionString = ConfigurationManager.ConnectionStrings[ConnectionString].ConnectionString; SqlConnectionStringBuilder SConn = new SqlConnectionStringBuilder(MyconnectionString); repDoc.DataSourceConnections[0].SetConnection(SConn.DataSource SConn.InitialCatalog SConn.UserID SConn.Password); repDoc.Load(Server.MapPath(Report/RptExpiryListByitem.rpt)); ParameterDiscreteValue objDiscreteValue; ParameterField objParameterField; objDiscreteValue = new ParameterDiscreteValue(); objParameterField = new ParameterField(); objDiscreteValue.Value =TextBox1.Text; objParameterField = CrystalReportViewer1.ParameterFieldInfo[@strIDs]; objParameterField.CurrentValues.Add(objDiscreteValue); CrystalReportViewer1.ParameterFieldInfo.Add(objParameterField); objDiscreteValue.Value = TextBox2.Text; objParameterField = CrystalReportViewer1.ParameterFieldInfo[@intFilterType]; objParameterField.CurrentValues.Add(objDiscreteValue); CrystalReportViewer1.ParameterFieldInfo.Add(objParameterField); objDiscreteValue.Value = TextBox3.Text; objParameterField = CrystalReportViewer1.ParameterFieldInfo[@dtFromDate]; objParameterField.CurrentValues.Add(objDiscreteValue); CrystalReportViewer1.ParameterFieldInfo.Add(objParameterField); objDiscreteValue.Value = TextBox4.Text; objParameterField = CrystalReportViewer1.ParameterFieldInfo[@dtToDate]; objParameterField.CurrentValues.Add(objDiscreteValue); CrystalReportViewer1.ParameterFieldInfo.Add(objParameterField); CrystalReportViewer1.ReportSource =repDoc; } when i run my apllication and pass the parameter to the report its give the error .. System.NullReferenceException: Object reference not set to an instance of an object. at line string MyconnectionString = ConfigurationManager.ConnectionStrings[ConnectionString].ConnectionString; please anyone provide me the solution for this problem.. thanks

Manikavelu Velayutham · Answer

Here is the issue. You have stored the connectionstring in appsettings. Thats why the error occured. You have to fetch from appsettings using the below code string MyconnectionString = ConfigurationManager.AppSettings[ConnectionString].ToString();

vaquas khan · Answer

Dear Manikavelu Velayutham can u provide above code in c# i run my application on development server not IIS my web.config file(connection string ) is given below

Manikavelu Velayutham · Answer

There might be two reasons for this error. 1. Check in IIS whether the application pointing to correct web.config file. Becuase sometimes the virtual directory will be pointing to different web.config file. 2. Try the below code to read the connection string it will fetch it without any error. Public Shared Sub ReadConnectionStrings() ' Get the ConnectionStrings collection. Dim connections _ As ConnectionStringSettingsCollection = _ ConfigurationManager.ConnectionStrings If connections. Count 0 Then Console.WriteLine() Console.WriteLine( _ Using ConnectionStrings property. ) Console.WriteLine( _ Connection strings: ) ' Get the collection elements. For Each connection _ As ConnectionStringSettings In connections Dim name As String = connection.Name Dim provider As String = _ connection.ProviderName Dim connectionString As String = _ connection.ConnectionString Console.WriteLine( _ Name: {0}  name) Console.WriteLine( _ Connection string: {0}  _ connectionString) Console.WriteLine( _ Provider: {0}  provider) Next Else Console.WriteLine() Console.WriteLine( _ No connection string is defined. ) Console.WriteLine() End If End Sub 3. Check the name of connectionstring in the web.config file sometimes if its mismatches it will throw this error. 4. Try to add a quick watch while debugging and see what are all the values available in the configuratino manager. let me know if you still cant fix the issue