錯誤。 NullReferenceException異常是由用戶代碼未處理

Question

給我一個錯誤在這條線

string con = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].DefaultConnection1; 

這裏是我的web.config

add name="DefaultConnection1" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=aspnet-TicketsApp-20140304175334;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnet-TicketsApp-20140304175334.mdf" 
    providerName="System.Data.SqlClient" /> 

下面是我的代碼：

namespace TicketsApp 
    { 
public partial class SearchTickets : System.Web.UI.Page 
{ 
    DateTime startDate = new DateTime(); 
    DateTime endDate = new DateTime(); 
    string con = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].DefaultConnection1; 


    protected void Page_Load(object sender, EventArgs e) 
    { 
    } 

    protected void btnSearch_Click(object sender, EventArgs e) 
    { 
     startDate = CalStartDate.SelectedDate; 
     endDate = CalEndDate.SelectedDate; 



     //searches the database for events between the selected dates 
     DataAccess myData = new DataAccess(); 
     ArrayList parameters = new ArrayList(); 

     SqlDataReader results; 

     parameters.Add(new SqlParameter("@StartDate", startDate)); 
     parameters.Add(new SqlParameter("@EndDate", endDate)); 

     results = myData.GetDataReader("SearchTickets", con, parameters); 

     this.grdSearch.DataSource = results; 
     this.grdSearch.DataBind(); 
    } 

    protected void btnUpdate_Click(object sender, EventArgs e) 
    { 
     string sportName = ddlSportType.SelectedItem.Text; 

     DataAccess myData = new DataAccess(); 
     ArrayList parameters = new ArrayList(); 

     //updates the selection by the sport selected 
     SqlDataReader results; 

     parameters.Add(new SqlParameter("@SportName", sportName)); 

     results = myData.GetDataReader("SearchTicketsBySport", con, parameters); 

     this.grdUpdated.DataSource = results; 
     this.grdUpdated.DataBind(); 
    } 
} 

Answer 1

連接字符串被稱爲「DefaultConnection1」，但你正在尋找「ConnectionString」，這可能不存在於你的Web.config文件中。