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I want to make a text file from a linq query.
The point is that my query produces more than 3000 records each time and when I use foreach it takes 2 minutes to extract all records and fields data.
foreach (var query3 in query)
{
line += (string)query3.Name.Trim() +"\t"+(string)query3.Code.Trim()+"\n";
}
How can I export linq query to a text file or string variable??
my query is something like :
var Query=from c in db.Exp select c;
You shouldn't use string when you perform a lot of string appending. Since string is an immutable object, a new block of memory is allocated in each iteration. You should use StringBuilder instead:
StringBuilder line = new StringBuilder();
foreach (var q2 in query)
{
line.AppendFormat("{0}\t{1}\n", query3.Name.Trim(), query3.Code.Trim());
}
File.WriteAllText(#"...", line.ToString());
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I have a list of string like this:
List<string> KeyList=["AD","B","KT"]
I want to split each item in the list in such a way where the final list output is a list of strings with only 1 character.
e.g.
["A","D","B","K","T"]
I have tried doing KeyList.ToCharArray() but that does not work.
You could use the Select LINQ extension method to turn each string into a list of 1-character strings, then flatten the list with SelectMany:
var list = new List<string>{ "AB", "B", "KT" };
var newList = list.SelectMany(s => s.Select(c => new string(c, 1))).ToList();
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I want to achieve the same code logic using Linq basically or re factoring the code would be great.
List<PublisherDto> listOfMappedPublishers = new List<PublisherDto>();
listOfPublishers.ForEach(pub =>
{
PublisherDto publisher = new PublisherDto();
publisher.ApiKey = pub.ApiKey;
publisher.Name = pub.Name;
publisher.Password = pub.Password;
listOfMappedPublishers.Add(publisher);
});
return listOfMappedPublishers;
You can use Select and ToList as follow:
List<PublisherDto> listOfMappedPublishers = listOfPublishers.Select(i=> new PublisherDto()
{
ApiKey = i.ApiKey,
Name = i.Name,
Password = i.Password
}).ToList();
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I want to refactor the code, I need to make this code dynamic, how to do that, see below part?
public class Trv34
{
public string CustomerNumber
public string ProductName
}
Models.Trv34[] itemTrv34 = new Models.Trv34[3]
itemTrv34[0] = new Models.Trv34 {CustomerNumber ="1", ProductName="p1"}
itemTrv34[1] = new Models.Trv34 {CustomerNumber ="2", ProductName="p2"}
itemTrv34[2] = new Models.Trv34 {CustomerNumber ="3", ProductName="p3"}
request.VODB.Trv34= new Models.Trv34[] {
itemTrv34[0],
itemTrv34[1],
itemTrv34[2],
};
I want to replace this part with something dynamic instead
itemTrv34[0],
itemTrv34[1],
itemTrv34[2],
The easiest way that comes to mind is to use Linq:
request.VODB.Trv34 = itemTrv34.ToArray();
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This is the data from my input
{Test,Sample}
This is the data from my database
{C:\Users\Test,D:\DriveB\Sample\Test,C:\Users\Private\Item\LocationB}
My expected output is
{C:\Users\Test,D:\DriveB\Sample\Test}
How can I get results out using that input? So far I have tried using a for loop like this
var Count = Input.Count;
for(var i = 0; i < Count; i++)
{
data = data.Where(u => u.Location.Contains(Input[i])).ToList();
}
The variable data has already been extracted from the database and has a format like this
Id
Name
Location
FileType
But the problem is that when it goes past the first loop, it immediately eliminates the second inputs data.
var Count = Input.Count;
data = data.Where(x => input.Any(y => x.Location.Contains(y))).ToList();
}
would likely work. The use of Any means:
Get me any row from data where at least one of the entries from input is contained in (i.e. a substring of) the Location.
Use split by "," first
var input = new List<String>() { "Test", "Sample" };
var db = #"C:\Users\Test,D:\DriveB\Sample\Test,C:\Users\Private\Item\LocationB";
var result = db.Split(',').Where(p => input.Any(c => p.Contains(c))).ToList();
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I have got a requirement like I have got list of strings and I got dropdownlist items now we need to check whether the dropdownlist has all items in the give list of strings or not and i need to return the bool condition ...
for that purpose i have done like this ....
public static bool GetMacthedItems(DropDownList ddllist1, DropDownList ddllist2, string MatchedItem1, string MatchedItem2, string MatchedItem3)
{
bool results =true;
List<String> list1 = new List<String> {MatchedItem1, MatchedItem2, MatchedItem3};
if (ddllist1.SelectedValue.ToString() == MatchedItem1 && (list1.Any(x => x.Contains(ddllist2.SelectedValue.ToString()))))
{
results = false;
}
return results;
}
but the above condition is checking like whether the dropdownlist selected value is in that list or not ....
i want entire like all items in dropdownlist are in that list or not
would any one pls help on this ....
var allContained = ddlCountry.Items.Cast<ListItem>().Select(item => item.Value).All(item => lst.Contains(item.ToString());
Try this - for performance it will stop iterating once the condition is broken and return false by using a combination of All with Contains.