我有一个
table product with colums product_id
prodcut_name
category_id
another table category
category_id
category_name
我正在使用datagridview填充这些产品详细信息,工作正常
我需要获取datagridview中所选行的类别名称,因为我已经这样做….
private void productGridview_Cellclick(object sender,DataGridViewCellEventArgs e)
{
string productname = Convert.ToString(selectedRow.Cells["productnam"].Value);
var categoryids = from cats in abc.products
where cats.product_Name.Equals(productname)
select cats.category_Id;
var catogynames = from categorytypes in abc.categories
where categorytypes.category_Name.Equals(categoryids)
select categorytypes.category_Name;
string categorynames = catogynames;
}
得到了
error : cannot implicitly convert type sysytem.linq.iqueryble<string> to string ...
我需要做什么来获得productgridview productnam列中所选单元格的单个类别名称
任何建议..请..
非常感谢….
not supported exception:
Unable to create a constant value of type 'System.Object'. Only primitive types ('such as Int32,String,and Guid') are supported in this context.
解决方法
您的查询返回的行为类似于集合的查询对象.您可以使用First,FirstOrDefault,Single或SingleOrDefault分别从查询中检索第一个或单个项目.
var categoryid = (from cats in abc.products
where cats.product_Name.Equals(productname)
select cats.category_Id).SingleOrDefault();
string categoryname = (from categorytypes in abc.categories
where categorytypes.category_Name.Equals(categoryid)
select categorytypes.category_Name).SingleOrDefault();
