/// <summary>
/// Provides a search for company name
/// </summary>
/// <param name="value">text to use for filter</param>
/// <param name="options">Type of search</param>
/// <remarks>
/// By default EF is case sensitive. Here we use ToLower to allow
/// case insensitive search but a fragile method is modifying the underlying table
/// https://milinaudara.wordpress.com/2015/02/04/case-sensitive-search-using-entity-framework-with-custom-annotation/
/// </remarks>
public void CompanyNameFilter(string value, FilterOptions options)
{
using (NorthWindEntity context = new NorthWindEntity())
{
switch (options)
{
case FilterOptions.StartsWith:
DataSource = context.Customers.Filter(cust => cust.CompanyName.ToLower().StartsWith(value.ToLower())).ToList();
break;
case FilterOptions.Contains:
DataSource = context.Customers.Filter(cust => cust.CompanyName.ToLower().Contains(value.ToLower())).ToList();
break;
case FilterOptions.EndsWith:
DataSource = context.Customers.Filter(cust => cust.CompanyName.ToLower().EndsWith(value.ToLower())).ToList();
break;
case FilterOptions.Equals:
DataSource = context.Customers.Filter(cust => cust.CompanyName.Equals(value, StringComparison.OrdinalIgnoreCase)).ToList();
break;
default:
break;
}
}
}
/// <summary>
/// Provides a method to update an existing customer and check for validation errors.
/// If there are issues in validation the entry is reverted back to it's former state.
///
/// Also, the validation errors are reported back to the user interface.
///
/// </summary>
/// <param name="EditedCustomer"></param>
/// <returns></returns>
public bool UpdateCustomer(Customer EditedCustomer)
{
using (NorthWindEntity context = new NorthWindEntity())
{
try
{
context.Entry(EditedCustomer).State = EntityState.Modified;
context.SaveChanges();
ValidationMessage = "";
return true;
}
catch (System.Data.Entity.Validation.DbEntityValidationException ef)
{
UndoAll(context);
ValidationMessage = ef.DbEntityValidationExceptionToString();
return false;
}
catch (Exception ex)
{
UndoAll(context);
ValidationMessage = "Update failed";
return false;
}
}
}
public void GetCustomers()
{
using (NorthWindEntity context = new NorthWindEntity())
{
DataSource = context.Customers.Select(cust => cust).ToList();
}
}
/// <summary>
/// Return a distinct list of contact titles
/// </summary>
/// <remarks>
/// In a normalized database the titles would be in a reference table.
/// </remarks>
public void GetContactTitles()
{
using (NorthWindEntity context = new NorthWindEntity())
{
ContactList = context
.Customers
.DistinctBy(cust => cust.ContactTitle)
.OrderBy(cust => cust.ContactTitle)
.Select(cust => cust.ContactTitle)
.ToList();
}
}
/// <summary>
/// Shows how to get column names for Customer table
/// </summary>
private void GetColumNames()
{
ColumnNames = new List <string>();
using (NorthWindEntity context = new NorthWindEntity())
{
var objectContext = ((IObjectContextAdapter)context).ObjectContext;
var storageMetadata = ((EntityConnection)objectContext.Connection).GetMetadataWorkspace().GetItems(DataSpace.SSpace);
var entityProps = (from sm in storageMetadata where sm.BuiltInTypeKind == BuiltInTypeKind.EntityType select sm as EntityType);
// For your project, open the model browser to get the name for the model, will have namespace.Store
var metaData = (from m in entityProps where m.FullName == "NORTHWNDModel.Store.Customers" select m.DeclaredProperties).ToList();
foreach (var topItem in metaData)
{
foreach (var item in topItem)
{
ColumnNames.Add(item.Name);
}
}
}
}
