Error CS0029 cannot implicitly convert type 'system.collections.generic.list to 'system.collections.generic.list

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1.44/5 (2 votes)

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Dear All

I have a query that works well (in LINQPap), but when is running in my project I recive an error message.

This is the class

public class cl_ELAB
{

    public int id_pro{ get; set; }
    public string c_pro { get; set; }
    public int id_reg { get; set; }
    public int id_per { get; set; }
    public string c_per { get; set; }
    public string c_email { get; set; }
}

This is the message:

Error	CS0029	Cannot implicitly convert type 'System.Collections.Generic.List<<anonymous type: int id_pro, string c_pro, int id_reg, int id_per, string c_per, string c_email>>' to 'System.Collections.Generic.List<TAP_DAL.Dal.Dal_Tap_pro.cl_ELAB>'

Please let me know where i am going wrong.

What I have tried:

and this is the code

TAP_Entities ctx = CurrentDbContext;

List<cl_ELAB> aquery = new List<cl_ELAB>();

aquery = (from p in ctx.ty9_prog.Where(t => t.id_pro == 1234)
          join r in ctx.t11_reg on p.id_pro equals r.id_pro
          join s in ctx.t35_per on r.id_per equals s.id_per
          select new
          {
              id_pro = p.id_pro,
              c_pro= p.c_pro,
              id_reg = r.id_reg,
              id_per= s.id_per,
              c_per = s.c_per,
              c_email = s.c_email
          }).ToList();

Posted 20-Nov-21 0:56am

antobaro

Updated 24-Oct-22 8:41am

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Comments

Richard MacCutchan 20-Nov-21 8:01am

The definition of aquery is for a List<cl_ELAB> (whatever cl_ELAB is), but you are trying to store it as a List<id_pro c_pro, id_reg, id_per, c_per, c_email>. The two List types must match exactly.

BillWoodruff 20-Nov-21 8:03am

Maybe ?

).Cast<cl_elab>().ToList();

antobaro 21-Nov-21 11:08am

Thank you very much for your help. :-)

3 solutions

Solution 3

After getting this error:

Gravité	Code	Description	Projet	Fichier	Ligne	État de la suppression
Erreur	CS0029	Impossible de convertir implicitement le type 'System.Collections.ObjectModel.ReadOnlyCollection<OpenQA.Selenium.IWebElement>' en 'System.Collections.Generic.List<OpenQA.Selenium.WebElement>'

I escaped to copying:

/// List<WebElement> elementAs = driver.FindElements(By.TagName("body"));
List<WebElement> elementAs = new List<WebElement>();
foreach (WebElement ItemMatch in driver.FindElements(By.TagName("body")))
{
    elementAs.Append(ItemMatch);
}

Posted 24-Oct-22 8:41am

Member 15808241

Updated 24-Oct-22 8:50am

v6

Comments

Richard Deeming 25-Oct-22 8:51am

This question was solved almost a year ago, and your code has nothing to do with the question that was posted.

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Estys · Accepted Answer · 2021-11-20T01:15:00

The error is on a type conversion.
try

C#

aquery = (from p in ctx.ty9_prog.Where(t => t.id_pro == 1234)
          join r in ctx.t11_reg on p.id_pro equals r.id_pro
          join s in ctx.t35_per on r.id_per equals s.id_per
          select new cl_ELAB()
          {
              id_pro = p.id_pro,
              c_pro= p.c_pro,
              id_reg = r.id_reg,
              id_per= s.id_per,
              c_per = s.c_per,
              c_email = s.c_email
          }).ToList();

OriginalGriff · Accepted Answer · 2021-11-20T02:40:00

To add to what Estys has - rightly - said ...
When you use select new in a Linq query, it creates an anonymous type unless you explicitly specify the name of an existing type:

var x = (from p in ...
          select new
          {
          X = p.x,
          Y = P.y
          }).ToList();

var y = (from p in ...
          select new MyClass()
          {
          X = p.x,
          Y = P.y
          }).ToList();

The former create a list of an anonymous class, the second creates a list of MyClass objects. Even though the two classes contain identical data, and identical properties, the system cannot and will not consider them the same: MyClass could have methods delegates, events, fields, or even properties that are not a part of the anonymous type and so the two collections are not equivalent, and the anonymous type collection cannot be assigned to a variable of the named class collection.

Error CS0029 cannot implicitly convert type 'system.collections.generic.list to 'system.collections.generic.list

3 solutions

Solution 1

Solution 2

Solution 3

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