排序下拉列表

Question

我正在使用实体框架数据库，我希望从一个表中填充我的下拉列表，但顺序是正确的。

现在我使用的代码是：

var databaseList = from p in db.TECHNICAL_SKILLS
                   where p.skill_type == "Database"
                   select new EmployeeTechnicalSkillInfo
                       {
                           TechnicalSkillId = p.technical_skill_id,
                           SkillType = p.skill_type,
                           SkillName = p.skill_name
                       };

        List<object> sDataValue = new List<object>();
        sDataValue.Add("- Select -");
        sDataValue.Remove("Other");

        foreach (var vData in databaseList)
        {
            sDataValue.Add(vData.SkillName);
        }

        sDataValue.Add("Other");

        DropDownListDB.DataSource = sDataValue.ToArray();
        DropDownListDB.DataBind(); 

这是解决方案

    var databaseList = from p in db.TECHNICAL_SKILLS
           where p.skill_type == "Database"
           orderby p.skill_name != "Other" descending, p.skill_name
           select new EmployeeTechnicalSkillInfo
               {
                   TechnicalSkillId = p.technical_skill_id,
                   SkillType = p.skill_type,
                   SkillName = p.skill_name
               };

Answer 1

您可以尝试使用带有布尔值的orderby。

orderby p.skill_name != "Other" descending, p.skill_name

在您的代码=>中

var databaseList = from p in db.TECHNICAL_SKILLS
               where p.skill_type == "Database"
               orderby p.skill_name != "Other" descending, p.skill_name
               select new EmployeeTechnicalSkillInfo
                   {
                       TechnicalSkillId = p.technical_skill_id,
                       SkillType = p.skill_type,
                       SkillName = p.skill_name
                   };

    List<object> sDataValue = new List<object>();
    sDataValue.Add("- Select -");

    foreach (var vData in databaseList)
    {
        sDataValue.Add(vData.SkillName);
    }

    DropDownListDB.DataSource = sDataValue.ToArray();
    DropDownListDB.DataBind(); 

Answer 2

从列表中删除条目-Select-，并将其作为第一项追加到List<object>中

List<object> sDataValue = new List<object>();
sDataValue.Add("-Select-");
foreach (var vData in databaseList){}

我想这是最简单的方法。

编辑

然后您将使用if/else，也许和

foreach (var vData in databaseList){} //fill your list
sDataValue.Add("-Other-");

Answer 3

就这么做吧：

将-Select-和Other从databaseList中删除如下：

var databaseList = from p in db.TECHNICAL_SKILLS
                   where p.skill_type == "Database"
                     && p.skill_name.ToLower() !="other"
                     && p.skill_name.ToLower() !="-select-"

                   select new EmployeeTechnicalSkillInfo
                       {
                           TechnicalSkillId = p.technical_skill_id,
                           SkillType = p.skill_type,
                           SkillName = p.skill_name
                       };

然后这样做：

DropDownListDB.DataSource = sDataValue.ToArray().OrderBy(s=>s);
DropDownListDB.Items.Insert(0, "-Select-");
DropDownListDB.Items.Add("Other");

如果您必须从数据库中引入-Select-和其他字段，那么将它们绑定到DropDownList，然后删除它们，然后再将它们插入到适当的位置是很小的开销。

您根本不需要从数据库中选择这两行。这样会更有效率。