Binding combo-box to Entity Data Model

pmcm

Hi, I'm trying to keep my data access code separate from the code behind my form. What I am trying to do is populate my combo-box with a list of CompanyNames here's how I'm trying to bind this combo-box to my Companies entity to retrieve the CompanyName:

private void frmMain_Load(object sender, EventArgs e)
{
dal = new DataAccessLayer();

cmbCompanyNameSearch.DataSource = dal.GetcmbCompanyList();

}

and here's the method in my DataAccessLayer:

public List<Companies> GetcmbCompanyList()
{
// Check we have an ObjectContext
if (entities == null) entities = new CompanySecretaryEntities();

    // Create a query from the entityset
ObjectQuery<Companies> companies = entities.Companies;
companies.MergeOption = MergeOption.AppendOnly;

// Define the query
var query = from c in entities.Companies
        select c.CompanyName;

// Execute the query
List<Companies> results = query.ToList();

// Return the results in a List
return results;

}

This is giving me the following error: Error 1 Cannot implicitly convert type 'System.Collections.Generic.List<string>' to 'System.Collections.Generic.List<CompanySecretary.Companies Can anyone point me in the correct direction? I know if I change select c.CompanyName; to be select c; removes the error message but I only want to select c.CompanyName in this instance

RobCroll

select c.CompanyName

is your problem. You are return a list of company names, not companies. Try

select c

Also the next problem you are going to have is with the ComboBox. Its only going to display the type of object "CompanySecretary.Companies". You'll need to check out the ComboBox's DisplayMember property to display the company name.

"You get that on the big jobs."

pmcm

thank you for the reply, I have managed to get it working by changing the code behind my form to be:

List companies = dal.GetCompanyList1();
cmbCompanyNameSearch.DataSource = companies;
cmbCompanyNameSearch.DisplayMember = "CompanyName";
cmbCompanyNameSearch.ValueMember = "CompanyID";

and renaming my DataAccessLayer method to GetCompanyList1