ComboBox.ValueMember和DisplayMember

Question

如何设置此值？我有一个DataTable，包含我想在组合框中设置的所有数据，但我无法找到如何设置它。

我试过

ComboBox1.DataSource = dataTable;
ComboBox1.ValueMember = "id"; // --> once hes here, he just jumps out the method
ComboBox1.DisplayMember = "name";

没有编译错误，警告，没有......只是跳出来！

这是填充DataTable的查询

"Select * from \"Table\""

我检查了调试器并填充了数据表。列名称是“id”和“name”。 ComboBox是空白的。我是第一次填写它！

Answer 1

您不应按此顺序设置列表框和/或组合框的datasource

ComboBox1.DataSource = dataTable;

ComboBox1.ValueMember = "id"; 

ComboBox1.DisplayMember = "name";

相反，这是正确的顺序：

ComboBox1.ValueMember = "id"; 

ComboBox1.DisplayMember = "name";

ComboBox1.DataSource = dataTable;

注意：设置datasource应该是最后一行。

如果您先设置datasource，SelectedIndexChanged事件将会触发，您可能会收到强制转换错误或其他异常。

Answer 2

  ComboBox1.DataSource= dt; //the data table which contains data
  ComboBox1.ValueMember = "id";   // column name which you want in SelectedValue
  ComboBox1.DisplayMember = "name"; // column name that you need to display as text

Answer 3

他们采取串......

ComboBox1.ValueMember = "id"; 
ComboBox1.DisplayMember = "name";

Answer 4

public class ComboDeger {
    private string yazi;
    private int deger;
    public ComboDeger(string stryazi, int strdeger) {
        this.yazi = stryazi;
        this.deger = strdeger;
    }
    public string yazisi {
        get {
            return yazi;
        }
    }
    public int degeri {
        get {
            return deger;
        }
    }
}
private void combobox_doldur() {
    ArrayList ComboDegerleri = new ArrayList();
    ComboDegerleri.Add(new ComboDeger("9 : NORMAL", 9));
    ComboDegerleri.Add(new ComboDeger("10 : ENGELLİ", 10));
    comboBox1.DataSource = ComboDegerleri;
    comboBox1.DisplayMember = "yazisi";
    comboBox1.ValueMember = "degeri";
}
private void Form3_Load(object sender, EventArgs e) {
    con.Open();
    combobox_doldur();

    // Populate the COMBOBOX using an array as DataSource.
}

Answer 5

我遇到了同样的麻烦。在我的例子中，SelectedIndexChanged事件触发并且只是跳出该方法。尝试不要使用SelectedIndexChanged事件。或类似的东西：

ComboBox1.SelectedIndexChanged -= new System.EventHandler(ComboBox1_SelectedIndexChanged); 
ComboBox1.DataSource = dataTable; 
ComboBox1.ValueMember = "id";  
ComboBox1.DisplayMember = "name";
ComboBox1.SelectedIndexChanged += new System.EventHandler(ComboBox1_SelectedIndexChanged);

它对我有用。 =）

Answer 6

使用键值对填充组合框

填充组合框的一种巧妙方法是将数据源设置为键值对列表。它也可能激发使用存储在某种列表中的数据：

//Some values to show in combobox
string[] ports= new string[3] {"COM1", "COM2", "COM3"};

//Set datasource to string array converted to list of keyvaluepairs
combobox.Datasource = ports.Select(p => new KeyValuePair<string, string>(p, p)).ToList();

//Configure the combo control
combobox.DisplayMember = "Key";
combobox.ValueMember = "Value";
combobox.SelectedValue = ports[0];

也可以使用以下语法填充数据源：

ports.Select(p => new { Key = p, Value = p }).ToList();

可以使用多个列列表的更多属性名称扩展技术。

Answer 7

您可以像这样指定

  ComboBox1.ValueMember = "id";  
  ComboBox1.DisplayMember = "name"; 

Answer 8

ComboBox1.ValueMember = dataTable.Columns["id"].ColumnsName;   // column name which the values are not visible 
ComboBox1.DisplayMember = dataTable.Columns ["name"].ColumnsName;
 /* 
       column name that you need to select item by proprity : 
ComboBox1.SelectedItem; 
Or   you can use easly this : 
ComboBox1.Text; 
*/

ComboBox1.DataSource= dataTable; //the data table which contains data 
// and this should be last :)