Asp.net mvc 3 回发时如何设置下拉列表的默认值

我正在与MVC3合作。 我有一个下拉列表，需要从数据库中设置默认值

当我在dropdownlist中选择一个值时，我会得到一个回发，并且我选择的值即使在回发之后也会被选中。如何在回发后再次将默认值

作为所选值

模型

namespace BugTracker.Models
{
    public class BugModel
    {
        public List<BugModel> InsertBug {get; set;}
        public List<BugModel> Bugs { get; set; }
        public Int16 BugID { get; set; }
        [Required(ErrorMessage = "Title is required")]
        public string Title { get; set; }
        [Required(ErrorMessage = "Description is required")]
        public string Description {get; set;}
        [Required(ErrorMessage = "Version is required")]
        public string Version { get; set; }
        [Required(ErrorMessage = "BuildNumber is required")]
        public string BuildNumber { get; set; }
        [Required(ErrorMessage = "CreatedDate is required")]
        public string CreatedDate { get; set; }
        [Required(ErrorMessage = "GetDate is required")]
        public string GetDate { get; set; }

        public List<BugModel> GetProjects { get; set; }
        public int ProjectID { get; set; }
        [Required(ErrorMessage = "ProjectName is required")]
        public string ProjectName { get; set; }

        public List<BugModel> GetEmployee {get; set;}
        public int EmployeeID { get; set; }
        public int CreatedByID { get; set; }
        [Required(ErrorMessage = "EmployeeName is required")]
        public string EmployeeName {get;set;}
        [Required(ErrorMessage = "CreatedBy is required")]
        public string CreatedBy { get; set; }

        public List<BugModel> GetCategory { get; set;}
        public int CategoryID { get; set; }
        [Required(ErrorMessage = "Category is required")]
        public string Category { get; set;}

        public List<BugModel> GetSeverity { get; set;}
        public int SeverityID { get; set; }
        [Required(ErrorMessage = "Severity is required")]
        public string Severity { get; set; }

        public List<BugModel> GetPriority { get; set; }
        public int PriorityID { get; set; }
        [Required(ErrorMessage = "Prirority is required")]
        public string Prirority { get; set;}

        public List<BugModel> GetReleasePhase { get; set;}
        public int ReleasePhaseID { get; set; }
        [Required(ErrorMessage = "ReleasePhase is required")]
        public string ReleasePhase { get; set;}

        public List<BugModel> GetTypes { get; set; }
        public int TypeID { get; set; }
        [Required(ErrorMessage = "Type is required")]
        public string Type { get; set; }
        public List<BugModel> GetBugHistory { get; set; }    
        [Required(ErrorMessage = "AssignTo is required")]
        public string AssignTo { get; set; }

    }
}

namespace-BugTracker.Models
{
公共类错误模型
{
公共列表插入错误{get；set；}
公共列表错误{get；set；}
public Int16 BugID{get；set；}
[必需（ErrorMessage=“需要标题”）]
公共字符串标题{get；set；}
[必需（ErrorMessage=“需要说明”）]
公共字符串说明{get；set；}
[必需（ErrorMessage=“需要版本”）]
公共字符串版本{get；set；}
[必需（ErrorMessage=“BuildNumber是必需的”）]
公共字符串BuildNumber{get；set；}
[必需（ErrorMessage=“CreatedDate是必需的”）]
公共字符串CreatedDate{get；set；}
[必需（ErrorMessage=“GetDate是必需的”）]
公共字符串GetDate{get；set；}
公共列表GetProjects{get；set；}
公共int ProjectID{get；set；}
[必需（ErrorMessage=“ProjectName是必需的”）]
公共字符串ProjectName{get；set；}
公共列表GetEmployee{get；set；}
public int EmployeeID{get；set；}
public int CreatedByID{get；set；}
[必需（ErrorMessage=“EmployeeName是必需的”）]
公共字符串EmployeeName{get；set；}
[必需（ErrorMessage=“CreatedBy是必需的”）]
通过{get；set；}创建的公共字符串
公共列表GetCategory{get；set；}
public int CategoryID{get；set；}
[必需（ErrorMessage=“类别是必需的”）]
公共字符串类别{get；set；}
公共列表GetSeverity{get；set；}
public int SeverityID{get；set；}
[必需（ErrorMessage=“严重性是必需的”）]
公共字符串严重性{get；set；}
公共列表GetPriority{get；set；}
public int PriorityID{get；set；}
[必需（ErrorMessage=“Prirority is Required”）]
公共字符串优先级{get；set；}
公共列表GetReleasePhase{get；set；}
public int ReleasePhaseID{get；set；}
[必需（ErrorMessage=“需要发布阶段”）]
公共字符串释放阶段{get；set；}
公共列表GetTypes{get；set；}
公共int类型ID{get；set；}
[必需（ErrorMessage=“Type is Required”）]
公共字符串类型{get；set；}
公共列表GetBugHistory{get；set；}
[必需（ErrorMessage=“AssignTo是必需的”）]
公共字符串赋值给{get；set；}
}
}

控制器

[AcceptVerbs(HttpVerbs.Post)]    
public ActionResult BugDetails(FormCollection form,string Projects,string Prirority,string CreatedBy,BugModel model)    
{
var modelList = new List();    
ViewBag.Projects = new SelectList(GetProjects(), "ProjectId", "ProjectName");    
ViewBag.Prirority = new SelectList(GetPriority(), "PriorityID", "Prirority");    
ViewBag.CreatedBy = new SelectList(GetEmployee(), "EmployeeID", "EmployeeName");    
using (SqlConnection conn = new SqlConnection(@"Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=BugtrackerNew;Data Source=SSDEV5-HP\SQLEXPRESS"))    
{    
    SqlCommand dCmd = new SqlCommand("Filter", conn);    
    dCmd.CommandType = CommandType.StoredProcedure;    
    conn.Open();    
    dCmd.Parameters.Add(new SqlParameter("@ProjectID", Projects));    
    dCmd.Parameters.Add(new SqlParameter("@PriorityID",Prirority));    
    dCmd.Parameters.Add(new SqlParameter("@CreatedByID",CreatedBy));    
    SqlDataAdapter da = new SqlDataAdapter(dCmd);    
    DataSet ds = new DataSet();    
    da.Fill(ds);
    for (int i = 0; i <= ds.Tables[0].Rows.Count - 1; i++)    
    {
        model.BugID = Convert.ToInt16(ds.Tables[0].Rows[i]["BugID"]);    
        model.Title = ds.Tables[0].Rows[i]["Title"].ToString();    
        model.Description = ds.Tables[0].Rows[i]["Description"].ToString();            
        conn.Close();             
        return View(modelList);
    }
}

[AcceptVerbs（HttpVerbs.Post）]
public ActionResult BugDetails（FormCollection表单、字符串项目、字符串优先级、字符串CreatedBy、BugModel模型）
{
var modelList=新列表（）；
ViewBag.Projects=新建选择列表（GetProjects（），“ProjectId”，“ProjectName”）；
ViewBag.Prirority=新选择列表（GetPriority（），“PriorityID”，“Prirority”）；
ViewBag.CreatedBy=新建SelectList（GetEmployee（），“EmployeeID”，“EmployeeName”）；
使用（SqlConnection conn=newsqlconnection（@“集成安全性=SSPI；持久安全性信息=False；初始目录=BugtrackerNew；数据源=SSDEV5-HP\SQLEXPRESS”））
{    
SqlCommand dCmd=新的SqlCommand（“过滤器”，conn）；
dCmd.CommandType=CommandType.StoredProcess；
conn.Open（）；
Add（新的SqlParameter（“@ProjectID”，Projects））；
Add（新的SqlParameter（“@PriorityID”，Prirority））；
Add（新的SqlParameter（“@CreatedByID”，CreatedBy））；
SqlDataAdapter da=新的SqlDataAdapter（dCmd）；
数据集ds=新数据集（）；
da.填充（ds）；
对于（int i=0；i

现在，我想在页面发回时获取默认值。但是在MVC中，我们没有页面加载方法，所以我如何做到这一点？

这篇文章可能会帮助您复制页面

using (Html.BeginForm())    
{ %>   
<%: Html.DropDownList("Projects", (SelectList)ViewBag.Projects)%>    
<%: Html.DropDownList("Prirority", (SelectList)ViewBag.Prirority, "Select Project")%>  
<%: Html.DropDownList("CreatedBy", (SelectList)ViewBag.CreatedBy, "--Select Project--")%>