Value cannot be null. Parameter name: String

Question

I got this error always and it prevents from insert to database this is may code for error line int id = Int32.Parse(Request.QueryString['Id']); the id id the column defined as auto increment with I do not need to insert to it please help

Manas Mohapatra · Answer

What error you are getting when your code is executing for insert purpose. Please provide details.

Joma Alrzini · Answer

thanks Manas my error is fixed bu the inserting still not working this is the code could please check it if (!String.IsNullOrEmpty(txtContent.Text)) // Label7.Text = "Please select User Role"; //else { SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString); SqlCommand insert = new SqlCommand("insert into dbo.News(news, date, user) values(@News, @Date, @UserName)", conn); Int32 id = 0; if (Request.QueryString["Id"] != null) { id = Int32.Parse(Request.QueryString["Id"]); } // int id = Int32.Parse(Request.QueryString["Id"]); insert.Parameters.AddWithValue("@News", txtContent.Text); insert.Parameters.AddWithValue("@UserName", Session["Full_Name"].ToString()); insert.Parameters.AddWithValue("@Date", DateTime.Now); try { conn.Open(); insert.ExecuteNonQuery(); txtContent.Text = ""; // Response.Redirect("ACourseManagement.aspx"); } catch { // Label7.Visible = false; Label10.Text = "Error when saving on database"; conn.Close(); } } I always got the catch exception I appreciate that very much

Manas Mohapatra · Answer

Mostly you querystringvalue is null. And when it is converting null to integer it throws you exception. So check null before your conversion like below: Int32 id =0; if (Request.QueryString[ "Id" ] != null ) { id =Int32.Parse(Request.QueryString[ "Id" ]); }

Joma Alrzini · Answer

thanks I got the error in catch block which shows the inserting not complete And when I checked the table there is no thing inserted

Value cannot be null. Parameter name: String

Answers (4)