System.Data.SqlClient.SqlException：スカラー変数 "@LocationID"を宣言しなければなりません。 MVCにおける

Question

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Must declare the scalar variable "@LocationID".

Source Error:

Line 43: Line 44: conn.Open(); Line 45:
adapter.Fill(dt); Line 46: conn.Close(); Line 47:

Source File: C:\Users\Dev D\Documents\Visual Studio 2015\Projects\MySafar\MySafar\Models\DBUtility.cs Line: 45

Location.cs

public ActionResult Location_Edit() 
{ 
      Location l = new Location(); 
      l.LocationID = Convert.ToInt32(Request.QueryString["ID"]); 
      l.SelectByPK(); 

      return View(l) 
} 

[HttpPost] 
public ActionResult Location_List_Edit() 
{ 
      Location l = new Location(); 
      l.LocationID = Convert.ToInt32(Request.QueryString["ID"]); 
      l.LocationName = Request.Form["LocationName"]; 
      l.PhotoPath = Request.Form["PhotoPath"]; 
      l.Details = Request.Form[" 
      l.CityID = Request.Form["CityID"]; 

      l.Update(); 

      return View("Location_List", new DataTable()); 
} 

DBUtility.cs（Modelクラス変更インサートのデータベースメソッドの定義とデータを選択AdminControllerにおけるビューの（Modelクラス）

public class Location 
{ 
     public int LocationID; 
     public string LocationName; 
     public string PhotoPath; 
     public string Details; 
     public string CityID; 
}   

public int Update() 
{ 
      string query = "UPDATE Location SET LocationName = @LocationName, PhotoPath = @PhotoPath, Details = @Details, CityID = @CityID WHERE LocationID = @LocationID"; 
      List<SqlParameter> parameters = new List<SqlParameter>(); 
      parameters.Add(new SqlParameter("@LocationID", this.LocationID)); 
      parameters.Add(new SqlParameter("@LocationName", this.LocationName)); 
      parameters.Add(new SqlParameter("@PhotoPath", this.PhotoPath)); 
      parameters.Add(new SqlParameter("@Details", this.Details)); 
      parameters.Add(new SqlParameter("@CityID", this.CityID)); 

      return DBUtility.ModifyData(query, parameters); 
} 

public bool SelectByPK() 
{ 
      string query = "SELECT * FROM Location WHERE LocationID = @LocationID"; 
      List<SqlParameter> parameters = new List<SqlParameter>(); 
      parameters.Add(new SqlParameter("@LocationID", this.LocationID)); 

      DataTable dt = DBUtility.SelectData(query, parameters); 

      if (dt.Rows.Count > 0) 
      { 
       this.LocationName = dt.Rows[0]["LocationName"].ToString(); 
       this.PhotoPath = dt.Rows[0]["PhotoPath"].ToString(); 
       this.Details = dt.Rows[0]["Details"].ToString(); 
       //this.CityID = Convert.ToInt32(dt.Rows[0]["CityID"]); 
       this.CityID = dt.Rows[0]["CityID"].ToString(); 

       return true; 
      } 
      else 
      { 
       return false; 
      } 
     } 
} 

方法）

public static DataTable SelectData(String query, List<SqlParameter> parameter) 
{ 
      SqlConnection conn = new SqlConnection(); 
      conn.ConnectionString = "Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFilename=\"C:\\Users\\Dev D\\Documents\\Visual Studio 2015\\Projects\\MySafar\\MySafar\\App_Data\\MySafarDB.mdf\";Integrated Security=True"; 

      SqlCommand command = new SqlCommand(); 
      command.Connection = conn; 

      command.CommandText = query; 

      DataTable dt = new DataTable(); 
      SqlDataAdapter adapter = new SqlDataAdapter(); 
      adapter.SelectCommand = command; 

      conn.Open(); 
      adapter.Fill(dt); 
      conn.Close(); 

      return dt; 
} 

Answer 1

この方法では問題があります

public static DataTable SelectData(String query, List<SqlParameter> parameter) 

heereあなたはcommandパラメータリストに追加List<SqlParameter> parameterを渡したがされていません。

これが原因でエラーが発生します。下記のようにパラメータを追加し、このコード行をメソッドに追加します。

foreach(var param in List<SqlParameter> parameter)) 
    command.Parameters.Add(param);