Develop Reference

Retrieve List<Object> to List<String> [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
Currently, I have a List<object> like this: List<USER>.
In User class, I have column named UserName.
I want to retrieve this column to List<string>.
How can it work without using foreach for List<USER>?
Thanks.

You can use LINQ:
List<string> userNames = users.Select(u => u.UserName).ToList();

In addition to Tim Schmelter post:
For casting IEnumerable<object> to IEnumerable<USER> you may use Cast<T> or OfType<T> method.
This can be written as follows:
var userNames = users.Cast<USER>.Select(u => u.UserName).ToList();

Creating .json file [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I have created JSON using following code.
List<int> _data = new List<int>();
foreach (DataRow row in dt.Rows)
{
_data.Add((int)row["Id"]);
}
JavaScriptSerializer jss = new JavaScriptSerializer();
chartData = jss.Serialize(_data);
Now can anyone tell me how do I save this is something like data.json? I want to write it into a file.

The Serialize method returns a String, doesn't it? So you can just use File.WriteAllText().

Need to convert SQL to Linq-To-SQL [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 8 years ago.
Improve this question
select cast(' ' as varchar(1000)) as myfield, otherfield
from tab1;
I need to convert above SQL to Linq-To-Sql.

Maybe:
from item in dataContext.Items
select new { MyField = "", Item = item };
Unfortunately, AMAIK, there is no way to declare * in projection in LINQ. Thus to have all other fields alongside your MyField field, you should write them all.

how do I write this query in linq ( c# )? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
Select * from table
where Numero_Operacion in
(
Select Numero_Operacion from table
group by Numero_Operacion
having count(Numero_Operacion)>1
)
THANKS!

It would be something like this
<Table>.GroupBy(x => x.Numero_Operacion)
.Where(x => x.Count() > 1)
.SelectMany(x => x)

How to search through all items of a combobox in C#? [closed]

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 9 years ago.
Improve this question
I have a combobox, and I would like to search through every element in it.
How can I do this? (also the number of items is not the same everytime, but this is not so important).
I am using c# windows form application.

you can do this
for (int i = 0; i < myComboBox.Items.Count; i++)
{
string value = myComboBox.GetItemText(myComboBox.Items[i]);
}

Use a foreach loop. It will iterate all your items of ComboBox regardless of their count, e.g.
foreach(var item in myComboBox.Items)
{
// do something with your item
}