我有一个简单的Web应用程序，我使用Entity Framework将一些数据添加到数据库，然后在下拉列表中填充它，我可以从中选择要删除的元组。我面临的问题是，当我添加新记录时，下拉列表不会被填充。我必须重新加载页面才能看到。以下是Page_Load方法背后的代码
protected void Page_Load(object sender, EventArgs e)
{
try
{
int token = Int32.Parse(Request.Cookies["EmcLabs"]["authToken"]);
EMCLabCustomerDataEntities context = new EMCLabCustomerDataEntities();
User u = new User();
u = context.Users.SingleOrDefault(x => x.Token == token);
lblJumboUsername.Text = u.Name;
lblJumboPost.Text = u.Post;
context.Dispose();
InitializePage();
}
catch (Exception)
{
Response.Cookies["EmcLabs"].Expires = DateTime.Now;
Response.Redirect("Login.aspx");
}
}
public void InitializePage()
{
EMCLabCustomerDataEntities context = new EMCLabCustomerDataEntities();
User usr = new User();
usr = context.Users.SingleOrDefault(x => x.Name == lblJumboUsername.Text);
if (usr.IsAdmin != 1)
{
divAdmin.Visible = false;
}
//Users
try
{
ddlUserList.DataSource = (from x in context.Users
where x.Name != lblJumboUsername.Text
select new
{
x.Name,
x.Id
}).ToList();
ddlUserList.DataTextField = "Name";
ddlUserList.DataValueField = "Id";
ddlUserList.DataBind();
ddlUserList.Items.Insert(0, new ListItem("Select User", "default"));
}
catch (Exception ex)
{
divMessages.Attributes.Add("class", "alert alert-danger");
lblMessage.Text += ex.Message;
}
}
以下是我必须添加和删除记录的代码。
rotected void btnAddUser_Click(object sender, EventArgs e)
{
try
{
User u = new User();
u.Email = txtEmail.Text.Trim();
u.Name = txtName.Text.Trim();
u.Password = txtRandomPass.Text;
u.Post = txtPost.Text.Trim();
u.Token = 0;
if (chkAdmin.Checked == true)
{
u.IsAdmin = 1;
}
else
{
u.IsAdmin = 0;
}
EMCLabCustomerDataEntities context = new EMCLabCustomerDataEntities();
if (true)
{
}
context.Users.Add(u);
context.SaveChanges();
divMessages.Attributes.Add("class", "alert alert-success");
lblMessage.Text = "New user added successfully.";
}
catch (Exception ex)
{
divMessages.Attributes.Add("class", "alert alert-danger");
lblMessage.Text = ex.Message;
}
}
protected void btnDeluser_Click(object sender, EventArgs e)
{
if (chkConfirmDelete.Checked == true)
{
try
{
if (ddlUserList.SelectedItem.Value != "default")
{
EMCLabCustomerDataEntities context = new EMCLabCustomerDataEntities();
User u = context.Users.Single(x => x.Name == ddlUserList.SelectedItem.Text);
context.Users.Remove(u);
context.SaveChanges();
divMessages.Attributes.Add("class", "alert alert-success");
lblMessage.Text = "User deleted successfully.";
}
else
{
divMessages.Attributes.Add("class", "alert alert-warning");
lblMessage.Text = "Select an user to remove first.";
}
}
catch (Exception ex)
{
divMessages.Attributes.Add("class", "alert alert-danger");
lblMessage.Text = ex.Message;
}
}
else
{
divMessages.Attributes.Add("class", "alert alert-warning");
lblMessage.Text = "Confirm before deleting.";
}
}