Linq 向dbContext查询添加联接时出现不明确的调用错误
我已经工作了几个小时来完成一些需要花一分钟时间使用TSQL的事情。当我将join语句添加到此方法时，VS会抱怨调用不明确。当我将鼠标悬停在“.Where”上时，弹出提示会从一个监视器转到另一个监视器，因此我很难从中提取任何非常有用的内容。如果我把.Join子句注释掉，一切都会好起来的 谢谢你的指导Linq 向dbContext查询添加联接时出现不明确的调用错误,linq,lambda,dbcontext,Linq,Lambda,Dbcontext,我已经工作了几个小时来完成一些需要花一分钟时间使用TSQL的事情。当我将join语句添加到此方法时，VS会抱怨调用不明确。当我将鼠标悬停在“.Where”上时，弹出提示会从一个监视器转到另一个监视器，因此我很难从中提取任何非常有用的内容。如果我把.Join子句注释掉，一切都会好起来的 谢谢你的指导 public List<CategoryDto> Categories(int departmentId) { IQueryable<Cate
public List<CategoryDto> Categories(int departmentId)
{
IQueryable<CategoryDto> categories = null;
List<CategoryDto> categoriesList = null;
using (var context = new ApplicationDbContext())
{
categories = context.Categories
.Join(context.CategoryImages, j => j.CategoryId, c => c.CategoryId,
(j, c) => new { CategoryImages = j, Categories = c })
.Where(c => c.DepartmentId == departmentId)
.OrderBy(c => c.Name)
.Select(category => new CategoryDto
{
CategoryId = category.CategoryId,
DepartmentId = category.DepartmentId,
Name = category.Name,
Description = category.Description,
DisplayOrderRank = category.DisplayOrderRank,
IsActive = category.IsActive
});
if (categories != null) categoriesList = categories.ToList();
}
return categoriesList;
}
公共列表类别（内部部门ID）
{
IQueryable categories=null；
List categoriesList=null；
使用（var context=new ApplicationDbContext（））
{
类别=上下文。类别
.Join（context.CategoryImages，j=>j.CategoryId，c=>c.CategoryId，
（j，c）=>新的{CategoryImages=j，Categories=c}）
.其中（c=>c.DepartmentId==DepartmentId）
.OrderBy（c=>c.Name）
.选择（类别=>new CategoryTo
{
CategoryId=category.CategoryId，
部门ID=类别。部门ID，
名称=类别。名称，
描述=类别。描述，
DisplayOrderRank=category.DisplayOrderRank，
IsActive=category.IsActive
});
如果（categories！=null）categoriesList=categories.ToList（）；
}
返回分类列表；
}
.Join(context.CategoryImages, j => j.CategoryId, c => c.CategoryId,
(j, c) => new { CategoryImages = j, Categories = c })
IQueryableCategoryImagesCategories.Where(x => x.Categories.DepartmentId == departmentId)
from c in context.Categories
join i in context.CategoryImages on c.CategoryId equals i.CategoryId
where c.DepartmentId == departmentId // now this is OK
Category.Images图像.Join(context.CategoryImages, j => j.CategoryId, c => c.CategoryId,
(j, c) => new { CategoryImages = j, Categories = c })
IQueryableCategoryImagesCategories.Where(x => x.Categories.DepartmentId == departmentId)
from c in context.Categories
join i in context.CategoryImages on c.CategoryId equals i.CategoryId
where c.DepartmentId == departmentId // now this is OK
Category.Images图像.Join(context.CategoryImages, j => j.CategoryId, c => c.CategoryId,
(j, c) => new { CategoryImages = j, Categories = c })
IQueryableCategoryImagesCategories.Where(x => x.Categories.DepartmentId == departmentId)
from c in context.Categories
join i in context.CategoryImages on c.CategoryId equals i.CategoryId
where c.DepartmentId == departmentId // now this is OK
Category.Images图像.Join(context.CategoryImages, j => j.CategoryId, c => c.CategoryId,
(j, c) => new { CategoryImages = j, Categories = c })
IQueryableCategoryImagesCategories.Where(x => x.Categories.DepartmentId == departmentId)
from c in context.Categories
join i in context.CategoryImages on c.CategoryId equals i.CategoryId
where c.DepartmentId == departmentId // now this is OK
但更好的做法是根本不编写连接并使用导航属性，如
Category.Images图像。类别在上下文中加入j。CategoryImages在j.CategoryId上等于c.CategoryId…jc。类别在上下文中加入j。CategoryImages在j.CategoryId上等于c.CategoryId…jc。类别在上下文中加入j。CategoryImages在j.CategoryId上等于c.CategoryId…jc。类别在上下文中加入j。CategoryImages在j.CategoryId上等于c.CategoryId…jc