怎么不重復名稱出現在組合框c＃

Question

我遇到了一個問題，我似乎無法使組合框中的名稱出現一次而不是多次。 我的代碼中是否有任何導致此問題的內容？ 任何幫助將不勝感激。

下面是將名稱鏈接到組合框的代碼。

private void Create_EmpDetails_Load(object sender, EventArgs e)
    {
        using (satsEntities Setupctx = new satsEntities())
        {
            var viewEmpName = (from viewEN in Setupctx.employees
                               join ufi u in Setupctx.ufis on viewEN.UFISID equals u.UFISID
                               select new { u.EmployeeName , u.UFISID}).Distinct().ToList();

            cbName.DataSource = viewEmpName;
            cbName.DisplayMember = "EmployeeName";
            cbName.ValueMember = "EmployeeName";
            //cbName.ValueMember = "UFISID";

        }
    }

Answer 1

這些行中的每一行都有不同的UFISID ，因此Distinct()不會刪除它們。

聽起來你只想向員工展示：

cbName.DataSource = Setupctx.Employees;

Answer 2

可能，你可以替換它

select new { u.EmployeeName , u.UFISID}

同

select new { u.EmployeeName }

Answer 3

我編輯了我的代碼，我設法只顯示1個名稱而不是多個記錄。

private void Create_EmpDetails_Load(object sender, EventArgs e)
    {
        using (satsEntities Setupctx = new satsEntities())
        {
            var viewEmpName = (from viewEN in Setupctx.employees
                               join ufi u in Setupctx.ufis on viewEN.UFISID equals u.UFISID
                               select new { u.EmployeeName }).Distinct().ToList();

            cbName.DataSource = viewEmpName;
            cbName.DisplayMember = "EmployeeName";
            cbName.ValueMember = "EmployeeName";
            //cbName.ValueMember = "UFISID";

        }
    }

Answer 4

在combobaxes中，我們為用戶顯示字符串DisplayAdmber，並為我們顯示成員ID（對我們來說可能很重要）作為ValueMember。 我們有更多時間使用ID。 我的例子：

class Country
{
    public string Name { get; set; }
    public int ID { get; set; }
    public Country( int i,string s) { Name = s; ID = i; }
}

class ComboItem
{

    public string DisplayMember { get; set; }

    public int ValueMember { get; set; }

}


class ComboItemEqualityComparer : IEqualityComparer<ComboItem>
{

    public bool Equals(ComboItem item1, ComboItem item2)
    {
        if (item1.ValueMember == item2.ValueMember && item1.DisplayMember == item2.DisplayMember)
        {
            return true;
        }

        return false;
    }


    public int GetHashCode(ComboItem item)
    {
        string str = item.DisplayMember + item.ValueMember;
        return str.GetHashCode();
    }
}

測試：

 List<Country> countries = new List<Country> {
                                  new Country(1,"UK"), 
                                  new Country(2,"Turkey"), 
                                  new Country(8,"Turkey"),
                                  new Country(5,"Turkey"), 
                                  new Country(2,"Turkey"),
                                  new Country(3,"USA") ,
                                  new Country(3,"USA")};  //.Distinct(new CountryEqualityComparer()).ToList();

        var Data = (from i in countries
                select new ComboItem { ValueMember = i.ID, DisplayMember = i.Name }).Distinct(new ComboItemEqualityComparer()).ToList();



        cbName.DataSource = Data;

        cbName.DisplayMember = "DisplayMember";
        cbName.ValueMember = "ValueMember";

有時我們的數據顯示名稱相同，但它們的ID不是。 我們可以將ComboItemEqualityComparer equals方法更改為：

public bool Equals(ComboItem item1, ComboItem item2)
    {
        if (item1.ValueMember == item2.ValueMember )
        {
            return true;
        }

        return false;
    }

請享用。

對於這個問題，我們可以：

....
select new ComboItem { ValueMember = u.UFISID, DisplayMember = u.EmployeeName }).Distinct(new yourIEqualityComparer()).ToList();