Question

在我的表格中，我有一个firstname和lastname字段，现在我想要的是将firstname和lastname设置为displaymember组合框，但我不知道怎么做。

像这样的东西

cmbEmployees.DataSource = GetEmployees();
//something like below line which doesn't work
cmbEmployees.DisplayMember = "lastname, first_name";     
cmbEmployees.ValueMember = "id";

我怎样才能做到这一点？因此lastname和firstname都会显示在combobox

中

Answer 1

此示例将指导您如何在不修改基类的情况下执行此操作。

首先，你可以给你的DisplayMember留下一个属性，比如说：

cmbEmployees.DisplayMember = "lastname";

现在，转到[设计]模式中的表单，右键单击ComboBox - ＆gt;属性。

在“属性”窗口的顶部，单击“事件（闪电图标）”，

在下面的事件列表中查找格式（在Property Changed下）并输入一些事件名称，例如：ComboBoxFormat，然后按Enter键。你会看到这个：

private void ComboBoxFormat(object sender, ListControlConvertEventArgs e)
{

}

现在写下以下几行：

private void ComboBoxFormat(object sender, ListControlConvertEventArgs e)
{
    // Assuming your class called Employee , and Firstname & Lastname are the fields
    string lastname = ((Employee)e.ListItem).Firstname;
    string firstname = ((Employee)e.ListItem).Lastname;
    e.Value = lastname + " " + firstname;
}

就是这样;）

Answer 2

假设您有一个这样的课程：

class Person
{
    public string FirstName
    {
        get;
        set;
    }

    public string LastName
    {
        get;
        set;
    }

    public string FullName
    {
        get
        {
            return LastName + ", " + FirstName;
        }
    }

    public Person(string firstname, string lastname)
    {
        FirstName = firstname;
        LastName = lastname;
    }
}

如果您没有FullName属性，只需以您希望显示名称的格式创建一个属性即可。然后将DisplayMember设置为FullName。

Answer 3

您的查询在 GetEmployees（）函数中应该是这样的。

"SELECT id,(lastname + ' ' + first_name) AS NAME FROM TABLE"

cmbEmployees.DataSource = GetEmployees();
cmbEmployees.DisplayMember = "NAME"; 
cmbEmployees.ValueMember = "id";

Answer 4

在C＃6中，在Employee类中创建readonly属性

public string FullName=>$"{lastname} {firstname}";

然后

cmbEmployees.DataSource = GetEmployees();
//something like below line which doesn't work
cmbEmployees.DisplayMember = "FullName";     
cmbEmployees.ValueMember = "id";

Answer 5

尝试以下方法之一：

新的Dictionary，其中包含连接字段值 - https://stackoverflow.com/a/1006588/1816426
计算列 - https://stackoverflow.com/a/1006546/1816426

Answer 6

创建视图[dbo]。[get_view] 如 SELECT CONCAT（sell_tb.Name，extra_tb.Name，purchase_tb.Name）AS名称FROM sell_tb FULL JOIN extra_tb ON extra_tb.E_ID = sell_tb.E_ID FULL JOIN Purchase_tb ON Purchase_tb.S_ID = sell_tb.S_ID;

      private void alldata1()
    {
        conn.Open();
        SqlCommand cmd = conn.CreateCommand();
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "select * from [get_view]";
        cmd.ExecuteNonQuery();
        DataTable dt = new DataTable();
        SqlDataAdapter sda = new SqlDataAdapter(cmd);
        sda.Fill(dt);
        comboBox1.DataSource = dt;
        comboBox1.DisplayMember = "Name";
        conn.Close();
    }

Answer 7

// Declare a class
private class ComboRec
   {
     public string ID { get; set; }
     public string FirstName { get; set; }
     public string LastName { get; set; }
     public string FullName { get; set; }
     public string Department { get; set; }
   }

   

    // Fill the Combo Items
    private void FillMyComboList()
            {
                EmployeesCombo.Items.Clear();
                EmployeesCombo.ValueMember = "ID";
                EmployeesCombo.DisplayMember = "FullName";
    
                MySqlCommand cmd = new MySqlCommand("select id, firstname, lastname, department from employees order by lastname, firstname", MyConnection);
                cmd.Transaction = myTransaction;
                MySqlDataReader rdr = cmd.ExecuteReader();
    
                ComboRec comborec;
    
                while (rdr.Read())
                {
                    comborec = new ComboRec();
                    comborec.ID = rdr["id"].ToString();
                    comborec.FirstName = rdr["firstname"].ToString();
                    comborec.LastName = rdr["lastname"].ToString();
                    comborec.FullName = rdr["lastname"].ToString() + ", " + rdr["firstname"].ToString();
                    comborec.Department = rdr["department"].ToString();
    
                    EmployeesCombo.Items.Add(comborec);
                }
    
                rdr.Close();
            }   
       
       
    // Get the values from combo
    string id = ((ComboRec)EmployeesCombo.SelectedItem).ID);
    string firstname = ((ComboRec)EmployeesCombo.SelectedItem).FirstName);
    string lastname = ((ComboRec)EmployeesCombo.SelectedItem).LastName);
    string fullname = ((ComboRec)EmployeesCombo.SelectedItem).FullName);
    string department = ((ComboRec)EmployeesCombo.SelectedItem).Department);

如何在C＃中的组合框显示成员中追加两个字段值

7 个答案: