编写winform(C#.net)程序中使用下拉框控件时，无法指定选择项的解决办法

首先定义类

  public  class ItemListHelp

    {

       public string text { get; set; }

       public string vlaue { get; set; }

    }

然后绑定ComboBox控件

  DataTable ta=GetAllFieldByLetterType();

            if(ta!=null)

            {

                drop_field.Items.Clear();

              

               

                foreach(DataRow row in ta.Rows)

                {

                    ItemListHelp item1=new ItemListHelp();

                    item1.text=row["fieldname"].ToString().Trim();

                    item1.vlaue=row["typename"].ToString().Trim();

                    if(item1.text!="")

                    drop_field.Items.Add(item1);

                }

                drop_field.DisplayMember = "text";

                drop_field.ValueMember = "value";

                //使第一项不为空

                drop_field.SelectedIndex = 0;

            }

这样绑定后ComcoBox的每一项都与ItemListHelp类相关联

设定选择项

//selectitem为要设定为选择项的显示文本

  if (selectitem != "")

            {

                foreach (ItemListHelp item in drop_field.Items)

                {

                    if (item.text == selectitem)

                    {

                        drop_field.SelectedItem = item;

                        break;

                    }

                }

            }