CODEWITHSUNDEEP
c#asp.netdatasource
Steven
Steven

Reputation: 13769

DataBind to ICollection<T>

My program should read and process data from legacy flat files.

I read the data into private ICollection<transaction> transactions;

public class transaction
{
    public int transactionNum;
    public DateTime transactionDate;
    public int orderNum;
    public string customerName;
    public Decimal amount;
}

How do I create a DataSource to this ICollection<T> (or a LINQ query of it), so that I can DataBind several control values to it?

Note: I have minimal LINQ knowledge. In the past, I could just drag a database table into my application.

Upvotes: 1

Views: 154

Answers (1)

Tim Schmelter
Tim Schmelter

Reputation: 460278

From your comment:

On the ASP.NET form, I have a CheckBoxList named customerCheckL. Upon loading the data file, the code should populate customerCheckL.Items with the list of distinct customer names. How do I do that? customerCheckL.DataSourceID = ???

That makes more sense. You could implement an EqulityComparer<transactions> class which compares by customer:

public class TransactionCustomerComparer : IEqualityComparer<transaction>
{
    public bool Equals(transaction x, transaction y)
    {
        if (x == null || y == null) return false;
        return x.customerName == y.customerName;
    }

    public int GetHashCode(transaction obj)
    {
        if (obj == null) return int.MinValue;
        return obj.customerName.GetHashCode();
    }
}

(Note that you can use this method in all Enumerable methods that allow to pass a custom comparer)

Then you can use Distinct to get a unique list. You just have to set the DataSource, DataTextField and DataValueField and DataBind the CheckBoxList.

var customerComparer = new TransactionCustomerComparer();
customerCheckL.DataSource = transactions.Distinct(customerComparer);
customerCheckL.DataTextField = "customerName";
customerCheckL.DataValueField = "transactionNum";
customerCheckL.DataBind();

Upvotes: 1

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