如何在C＃中编辑/更新集合中的数据

Question

I have a collection in my C# code

private ObservableCollection<UserForms> _userForms = 
    new ObservableCollection<UserForms>();

public ObservableCollection<UserForms> UserForms { get { return _userForms; } }

I am filling collection with 4 values

foreach (DataRow dr in DataTable.Rows)
{
                    UserForms.Add(new UserForms()
                    {
                        FormID = Convert.ToInt32(dr["FormID"]),
                        FormName = dr["FormName"].ToString(),
                        FromSyName = dr["FormSyName"].ToString(),
                        Visibility = false,
                        RoleAdd=false,
                        RoleEdit=false,
                        RoleDelete=false
                    });
}

I am filling this in Form_Load() event

Now I want to update

Visibility = true,
RoleAdd=true,
RoleEdit=true,
RoleDelete=true

in specified row in the collection.

Answer 1

You simply need to do the following:

UserForms[0].Visibility = true;

where "[0]" is the index.

Answer 2

If your ObservableCollection is enumerable (which collections usually are) you can use a foreach loop as follows:

foreach(UserForms uf in UserForms)
{
    if (uf.FormID > 10)
        uf.Visibility = true;
}

In the above code, I change the visibility of rows which their FormID is higher than 10.

Answer 3

Looks like you need filter out some items and then update them.

foreach(UserForms uf in UserForms.Where(i=>i.FormName == "FormName"/*put your filtering criteria here*/))
{
    uf.Visibility = true;
    // Set all needed properties here
}

Answer 4

You want to access the instance of collection.

_userForms.ToList().ForEach((f) => f.Visibility = true); 

or if you know the index and want to update individual item.

 _userForms[index].Visibility = true;

or for multiple filter items

 var filterColl = coll.Where((c)=> c.FormName.StartsWith("A"));
 filterColl.ToList().ForEach((f) => f.Visibility = true); 

hope this helps..