HTML/C# GridView не обновляется после внесения изменений.

Question

Я сделал довольно много поисковой системы, чтобы попытаться понять это, но пока не повезло. В основном я надеюсь, что кто-то может ID, почему мой GridView не обновляется, когда я заканчиваю редактирование строки. Я пытался проанализировать пример моего профессора, сделанный в классе, поэтому я могу закончить эту лабораторию, и, насколько я могу судить, я сделал все так же, как и он (за исключением изменения SQL-сервера). Лаборатория не закончила, у меня все еще есть компоненты для добавления, такие как код OnDelete, но ни одно из них не должно быть релевантным вызову обновления.

Default.aspx:

<%@ Page Title="" Language="C#" MasterPageFile="~/IT213.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> 

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"> 
</asp:Content> 
<asp:Content ID="Content2" ContentPlaceHolderID="cphMaster" Runat="Server"> 
    <h1> 
     Edit DB 
    </h1> 
    <br /> 
    <asp:gridview runat="server" ID="gvStudents" AutoGenerateColumns="False" HorizontalAlign="Center" AllowSorting="True" OnSorting="gvStudents_Sorting" OnRowEditing="gvStudents_RowEditing" OnRowUpdating="gvStudents_RowUpdating" CellPadding="4" ForeColor="#333333" GridLines="None" DataKeyNames="student"> 
     <AlternatingRowStyle BackColor="White" /> 
     <Columns> 
      <asp:TemplateField HeaderText="Student" SortExpression="student"> 
       <ItemTemplate> 
        <%# Eval("student") %> <%--This is required to bind the data column to the GridView column.--%> 
       </ItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Name" SortExpression="student_name"> 
       <ItemTemplate> 
        <%# Eval("student_name") %> 
       </ItemTemplate> 
       <EditItemTemplate> 
        <asp:TextBox ID="txtStudentName" Text='<%# Eval("student_name") %>' Columns='<%# getLength(Eval("student_name").ToString()) %>' runat="server"></asp:TextBox> 
       </EditItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Address" SortExpression="address"> 
       <ItemTemplate> 
        <%# Eval("address") %> 
       </ItemTemplate> 
       <EditItemTemplate> 
        <asp:TextBox ID="txtAddress" Text='<%# Eval("address") %>' Columns='<%# getLength(Eval("address").ToString()) %>' runat="server"></asp:TextBox> 
       </EditItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="City" SortExpression="city"> 
       <ItemTemplate> 
        <%# Eval("city") %> 
       </ItemTemplate> 
       <EditItemTemplate> 
        <asp:TextBox ID="txtCity" Text='<%# Eval("city") %>' Columns='<%# getLength(Eval("city").ToString()) %>' runat="server"></asp:TextBox> 
       </EditItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="State" SortExpression="state"> 
       <ItemTemplate> 
        <%# Eval("state") %> 
       </ItemTemplate> 
       <EditItemTemplate> 
        <asp:TextBox ID="txtState" Text='<%# Eval("state") %>' Columns='<%# getLength(Eval("state").ToString()) %>' runat="server"></asp:TextBox> 
       </EditItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Zip" SortExpression="zip"> 
       <ItemTemplate> 
        <%# Eval("zip") %> 
       </ItemTemplate> 
       <EditItemTemplate> 
        <asp:TextBox ID="txtZip" Text='<%# Eval("zip") %>' Columns='<%# getLength(Eval("zip").ToString()) %>' runat="server"></asp:TextBox> 
       </EditItemTemplate> 
      </asp:TemplateField> 
      <asp:TemplateField HeaderText="Sex" SortExpression="sex"> 
       <ItemTemplate> 
        <%# Eval("sex") %> 
       </ItemTemplate> 
       <EditItemTemplate> 
        <asp:TextBox ID="txtSex" Text='<%# Eval("sex") %>' Columns='<%# getLength(Eval("sex").ToString()) %>' runat="server"></asp:TextBox> 
       </EditItemTemplate> 
      </asp:TemplateField> 
      <asp:CommandField ShowEditButton="True" /> 
      <asp:CommandField ShowDeleteButton="True" /> 
     </Columns> 
     <EditRowStyle BackColor="#2461BF" /> 
     <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> 
     <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> 
     <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" /> 
     <RowStyle BackColor="#EFF3FB" /> 
     <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" /> 
     <SortedAscendingCellStyle BackColor="#F5F7FB" /> 
     <SortedAscendingHeaderStyle BackColor="#6D95E1" /> 
     <SortedDescendingCellStyle BackColor="#E9EBEF" /> 
     <SortedDescendingHeaderStyle BackColor="#4870BE" /> 
    </asp:gridview> 
</asp:Content> 

Default.aspx.cs:

protected void Page_Load(object sender, EventArgs e) 
{ 
    //Check if this is the first page load, if it is bind 
    if(!Page.IsPostBack) 
    { 
     bindStudents(); 
    }// end IsPostBack 
} // end Page_Load 

private void bindStudents() 
{ 
    // This sets where gvStudents gets its data, then binds them together. 
    gvStudents.DataSource = CMethods.returnTable("SELECT * FROM STUDENTS"); 
    gvStudents.DataBind(); 
} // end bindStudents 

private void bindStudents(string sort) 
{ 
    // This is the same as bindStudents, but also applies sorting 
    gvStudents.DataSource = CMethods.returnTable("SELECT * FROM STUDENTS ORDER BY " + sort); 
    gvStudents.DataBind(); 
} // end bindStudents + sort 

protected void gvStudents_Sorting(object sender, GridViewSortEventArgs e) 
{ 
    // This sets the SortExpression used by the GridView 
    bindStudents(e.SortExpression); 
    Session["sort"] = e.SortExpression; 
} // end gvStudents_Sorting 

protected void gvStudents_RowEditing(object sender, GridViewEditEventArgs e) 
{ 
    // Determine which row is being edited 
    gvStudents.EditIndex = e.NewEditIndex; 

    // preserve sort data when editing 
    if(Session["sort"] != null) 
    { 
     bindStudents(Session["sort"].ToString()); 
    } 
    else 
    { 
     bindStudents(); 
    } 
} // end gvStudents_RowEditing 

protected int getLength(string str) 
{ 
    // returns the length of str after triming trailing and leading white space 
    return str.Trim().Length; 
} // end getLength 

protected void gvStudents_RowUpdating(object sender, GridViewUpdateEventArgs e) 
{ 
    // Converts Datakey of the row being edited to int16 
    int student = Convert.ToInt16(gvStudents.DataKeys[e.RowIndex].Value); 

    // Retrieves the text inside the edit TextBoxes and places it in a local TextBox 
    TextBox txtStudentName = (TextBox)gvStudents.Rows[e.RowIndex].FindControl("txtStudentName"); 
    TextBox txtAddress = (TextBox)gvStudents.Rows[e.RowIndex].FindControl("txtAddress"); 
    TextBox txtCity = (TextBox)gvStudents.Rows[e.RowIndex].FindControl("txtCity"); 
    TextBox txtState = (TextBox)gvStudents.Rows[e.RowIndex].FindControl("txtState"); 
    TextBox txtZip = (TextBox)gvStudents.Rows[e.RowIndex].FindControl("txtZip"); 
    TextBox txtSex = (TextBox)gvStudents.Rows[e.RowIndex].FindControl("txtSex"); 

    // Stores an SQL statment as string 
    string sql = "UPDATE STUDENTS SET student_name=@student_name, " + 
            "address=@address, " + 
            "city=@city," + 
            "state=@state, " + 
            "zip=@zip, " + 
            "sex=@sex " + 
            "WHERE student=@student"; 

    // Runs previously saved sql statement using assigned parameters 
    CMethods.executeNonQuery(sql, "@student_name", txtStudentName.Text.Trim(), "@address", txtAddress.Text.Trim(), 
          "@city", txtCity.Text.Trim(), "@state", txtState.Text.Trim(), "@zip", txtZip.Text.Trim(), 
          "@sex", txtSex.Text.Trim()); 

    // Closes edit of selected row 
    gvStudents.EditIndex = -1; 

    // Preserves sort data 
    if(Session["sort"] != null) 
    { 
     bindStudents(Session["sort"].ToString()); 
    } 
    else 
    { 
     bindStudents(); 
    } 
} // end gvStudents_RowUpdating 

//private bool isStudent(int student) 
//{ 
// // loads table into memory 
// DataTable tbl = CMethods.returnTable("SELECT * FROM STUDENTS WHERE student=@student", "@student", student); 
// // checks if table is empty 
// if(tbl.Rows.Count > 0) 
// { 
//  return true; 
// } 
// else 
// { 
//  return false; 
// } 
//} // end isStudent 

CMethods класс:

public static double text2double(string str) 
{ 
    string temp = string.Empty; 
    bool blnIsFirstDecimal = true; 
    for (int i = 0; i < str.Length; i++) 
    { 
     if (Char.IsDigit(Convert.ToChar(str.Substring(i, 1)))) 
     { 
      temp += str.Substring(i, 1); 
     } 
     if (str.Substring(i, 1).Equals(".")) 
     { 
      if (blnIsFirstDecimal) 
      { 
       blnIsFirstDecimal = false; 
       temp += "."; 
      } 
     } 
    } //end for 
    if (temp.Trim().Length == 0) 
     return 0.0D; 
    else 
     return Convert.ToDouble(temp); 
} // end text2double 

public static DataTable returnTable(String CommandText, params Object[] values) 
{ 
    // Creates connection to SQL Database using login info provided via connection string in webconfig 
    SqlConnection sqlCon = new SqlConnection(ConfigurationManager.ConnectionStrings["Provider"].ConnectionString); 

    // Creates a new SQL command with the value passed to the method being the command, and a preassigned SQL connection 
    SqlCommand sqlCmd = new SqlCommand(CommandText, sqlCon); 

    // !!!!!!!!! Not sure why this is here. !!!!!!!!!!!! 
    for (int i = 0; i < values.Length; i += 2) 
    { 
     sqlCmd.Parameters.AddWithValue((String)values[i], values[i + 1]); 
    } // end for 

    // Creates new dataset, these contain tables and allows you to give those tables IDs. 
    DataSet dSet = new DataSet(); 

    // Used to read/retrieve(?) data from a DB 
    SqlDataAdapter dAdapt = new SqlDataAdapter(sqlCmd); 

    // Copies rows from source table to DataSet 
    dAdapt.Fill(dSet, "tbl"); 

    return dSet.Tables["tbl"]; 
} // end returnTable 

public static bool executeNonQuery(String CommandText, params Object[] values) 
{ 
    bool bln = true; 

    // Creates new sql connection using connection string "Provider" 
    SqlConnection con = 
     new SqlConnection(ConfigurationManager.ConnectionStrings["Provider"].ConnectionString); 

    // Creates a new SQL command with the value passed to the method being the command, and a preassigned SQL connection 
    SqlCommand cmd = new SqlCommand(CommandText, con); 

    // !!!!!!!!! Not sure why this is here. !!!!!!!!!!!! 
    for (int i = 0; i < values.Length; i += 2) 
    { 
     cmd.Parameters.AddWithValue((String)values[i], values[i + 1]); 
    } 
    try 
    { 
     con.Open(); // opens the previously created sqlconnection 
     cmd.ExecuteNonQuery(); // Executes a Transact-SQL statement against the connection, returns number of rows affected 
    } 
    catch (Exception ex) 
    { 
     bln = false; 
    } 
    finally 
    { 
     con.Close(); 
    } 
    return bln; 
} // end executeNonQuery 

Answer 1

Сон это прекрасная вещь, и поэтому SO. У другого пользователя действительно была аналогичная проблема, и хотя я не смог найти его сообщение вчера вечером, SO сделал ссылку сегодня утром.

https://stackoverflow.com/a/13939812/5924307

я пропускал параметр.

Bad Код:

CMethods.executeNonQuery(sql, "@student_name", txtStudentName.Text.Trim(), "@address", txtAddress.Text.Trim(), 
          "@city", txtCity.Text.Trim(), "@state", txtState.Text.Trim(), "@zip", txtZip.Text.Trim(), 
          "@sex", txtSex.Text.Trim()); 

Хороший код:

CMethods.executeNonQuery(sql, "@student_name", txtStudentName.Text.Trim(), "@address", txtAddress.Text.Trim(), 
           "@city", txtCity.Text.Trim(), "@state", txtState.Text.Trim(), "@zip", txtZip.Text.Trim(), 
           "@sex", txtSex.Text.Trim(), "@student", student);