C#webapi(2)更新数据库

【1】linq表达式

C#webapi(2)更新数据库

T_DATA_PE tp =new T_DATA_PE();
int unit=int.Parse(context.Request.Form["Unit"]);
int Style=int.Parse(context.Request.Form["style"]);
int Community=int.Parse(context.Request.Form["community"]);
DateTime Monitortime= Convert.ToDateTime(context.Request.Form["monitortime"]);
var data = ef.FindAll<T_DATA_PE>(x => x.Unit == unit && x.style == Style && x.community == Community && x.monitortime == Monitortime).FirstOrDefault();
tp = data;
/*tp.Unit = data.Unit;
tp.community = data.community;
tp.style = data.style;
tp.monitortime = data.monitortime;
tp.image1 = data.image1;
tp.image2 = data.image2;
tp.image3 = data.image3;*/

【2】linq---update报错

C#webapi(2)更新数据库

https://www.cnblogs.com/godbell/p/7360739.html

附加类型“AirQuality.Model.T_DATA_PE的实体失败，因为相同类型的其他实体已具有相同的主键值。在使用 "Attach" 方法或者将实体的状态设置为 "Unchanged" 或 "Modified" 时如果图形中的任何实体具有冲突键值，则可能会发生上述行为。这可能是因为某些实体是新的并且尚未接收数据库生成的键值。在此情况下，使用 "Add" 方法或者 "Added" 实体状态跟踪该图形，然后将非新实体的状态相应设置为 "Unchanged" 或 "Modified"。

bool addresult = ef.Update<T_DATA_PE>(tp);更新数据

https://blog.csdn.net/huqitu/article/details/3765069?utm_source=blogxgwz7

https://blog.csdn.net/txhdjackie/article/details/77531745

/bool addresult = ef.Update<T_DATA_PE>(tp);//直接更新会报错
ef.Delete<T_DATA_PE>(x => x.Unit == unit && x.style == Style && x.community == Community && x.monitortime == Monitortime);//删除原来的数据,然后再插入
List<T_DATA_PE> list = new List<T_DATA_PE>();
list.Add(tp);
int addresult = ef.Insert<T_DATA_PE>(list);

if (addresult >0)

【3】null.ToString()抛出异常

result.postid = temp.Rectification1.ToString() + " ; " + temp.Rectification2.ToString() + " ; " + temp.Rectification3.ToString() + " ; ";

null.ToString() 抛出异常

/// <summary>
/// 曝光问题解决操作页面
/// </summary>
/// <returns></returns>
[HttpGet, HttpPost, Route("SolveProblem")]
public PostResult SolveProblem()
{
PostResult result = new PostResult();
HttpContext context = HttpContext.Current;
//foreach (var key in context.Request.Form.AllKeys){}
T_DATA_PE tp =new T_DATA_PE();
var data = ef.FindAll<T_DATA_PE>(x => x.Unit == (int.Parse(context.Request.Form["Unit"])) && x.style == (int.Parse(context.Request.Form["style"])) && x.community == (int.Parse(context.Request.Form["community"])) && x.monitortime == Convert.ToDateTime(context.Request.Form["monitortime"])).FirstOrDefault();
tp.Unit = data.Unit;
tp.community = data.community;
tp.style = data.style;
tp.monitortime = data.monitortime;
tp.image1 = data.image1;
tp.image2 = data.image2;
tp.image3 = data.image3;
tp.Operator = context.Request.Form["Operator"];//解决人
tp.status = 1;//解决状态
tp.modifytime = Convert.ToDateTime(context.Request.Form["modifytime"]);
tp.solution = context.Request.Form["solution"];

try
{
System.Web.Mvc.Controller controller = new HomeController();

#region 上传图片
string path = "\\";// context.Request.Form["path"]

//用“,”分割文件流
var base64Code = context.Request.Form["base64Code1"].Split(',');
for (var i = 0; i < base64Code.Length; i++)
{
string str = base64Code[i];
string PicPath = System.Configuration.ConfigurationManager.AppSettings["PicPath"];
string fileExt = "jpg"; //文件扩展名，不含“.”
string newFileName = GetTimeStamp() + "_" + (i + 1) + "." + fileExt; //随机生成新的文件名
string pathY = System.Web.HttpContext.Current.Server.MapPath(path + "UploadImg\\solution\\yt\\");
if (!Directory.Exists(pathY))
{
Directory.CreateDirectory(pathY);
}
//保存图片路径--绝对路径
string newFilePath = System.Web.HttpContext.Current.Server.MapPath(path + "UploadImg\\solution\\yt\\" + newFileName);
//判断一下是否上传了图片
if (str != null)
{
Image img = Base64ToImg(str);//Image--using System.Drawing;
img.Save(newFilePath, System.Drawing.Imaging.ImageFormat.Png);
string ypath = PicPath + "UploadImg/solution/yt/" + newFileName;
if (i == 0)
{
tp.Rectification1 = ypath;
}
else if (i == 1)
{
tp.Rectification2 = ypath;
}
else if (i == 2)
{
tp.Rectification3 = ypath;
}

}
}

List<T_DATA_PE> list = new List<T_DATA_PE>();
list.Add(tp);
bool addresult = ef.Update<T_DATA_PE>(tp);
if (addresult ==true)
{
T_DATA_PE temp = ef.FindAll<T_DATA_PE>(p => p.Unit == tp.Unit && p.style == tp.style && p.community == tp.community).OrderByDescending(p => p.monitortime).FirstOrDefault();
result.flag = true;
result.msg = "发布成功";
result.postid = temp.Rectification1.ToString() + " ; " + temp.Rectification2.ToString() + " ; " + temp.Rectification3.ToString() + " ; ";
}
else
{
result.flag = false;
result.msg = "发布失败";
result.postid = "";
}
}
catch (Exception e)
{

result.flag = false;
result.msg = "接口异常:" + e.ToString();
result.postid = "";
}
return result;
}

/// <summary>
/// 增加巡查返回结果
/// </summary>
public class PostResult
{
public bool flag { get; set; }
public string msg { get; set; }
public string postid { get; set; }
}