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();

How can I convert DIA_User[] to List<DIA_User> [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
I used wcf service to work directly to database.
And the result I got as this format: DIA_User[]
I can use linq for this as select, find,... but I dont know how to convert to List<DIA_User>
Please advise.
Thank you very much.

Just use ToList() method, which is an extension method on IEnumerable<>
DIA_User[] x = new DIA_User[] {};
List<DIA_User> y = x.ToList();

List<DIA_USER> users = new List<DIA_USER>(diaUserArray);

var arrayUser = new DIA_User[]();
var listUsers = arrayUser.ToList();
BTW, you can configure your WCF service to send Lists instead of Arrays.

Update DataTable records by Id 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
Could anyone please suggest, I have a datatable with 100 records and want to update any 1 specific record based on id.

Here is an example, maybe it helps even if your reqirement is not that clear:
DataRow row = tableWith100Rows.AsEnumerable()
.FirstOrDefault(r => r.Field<int>("ID") == 4711);
if(row != null)
row.SetField("ColumnToUpdate", "new value");

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
}