How to track event in Audit.Net with SqlDataProvider

Question

I'm trying to audit db actions using SqlDataProvider .

Global.asax.cs

                Audit.Core.Configuration.DataProvider = new SqlDataProvider()
        {
            ConnectionString =  "...",
            Schema = "dbo",
            TableName = "Event",
            IdColumnName = "EventId",
            JsonColumnName = "JsonData",
            LastUpdatedDateColumnName = "LastUpdatedDate",

            CustomColumns = new List<CustomColumn>()
        {

            new CustomColumn("EventType", ev => ev.EventType),
            new CustomColumn("ModuleName", ev => "AuditTrail")
        }
        };

if I add custom column like following

    new CustomColumn("StartDate", ev=>ev.StartDate),
    new CustomColumn("EndDate", ev=>ev.EndDate),
    new CustomColumn("Duration", ev=>ev.Duration),
    new CustomColumn("Target", ev=>ev.Target),
    new CustomColumn("Comments", ev=>ev.Comments),
    new CustomColumn("Environment", ev=> ev.Environment),

it throws an exception "No mapping exists from object type Audit.Core.AuditEventEnvironment to a known managed provider native type"

How can I track the event here. Basically I want to insert jasonData field value into several fields.

Context Changes

    public override int SaveChanges()
    {
        return _helper.SaveChanges(_auditContext, () => base.SaveChanges());
    }

    public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
    {
        return await _helper.SaveChangesAsync(_auditContext, () => base.SaveChangesAsync(cancellationToken));
    }

Answer 1

It was an issue in data types. The correct code should be

     Audit.Core.Configuration.DataProvider = new SqlDataProvider()
    {
        ConnectionString =  "...",
        Schema = "dbo",
        TableName = "Event",
        IdColumnName = "EventId",
        JsonColumnName = "JsonData",
        LastUpdatedDateColumnName = "LastUpdatedDate",

        CustomColumns = new List<CustomColumn>()
    {

        new CustomColumn("EventType", ev => ev.EventType),
        new CustomColumn("ModuleName", ev => "AuditTrail"),
        new CustomColumn("StartDate", ev=>Convert.ToDateTime(ev.StartDate)),
        new CustomColumn("EndDate", ev=>Convert.ToDateTime(ev.EndDate)),
        new CustomColumn("Duration", ev=>Convert.ToInt32(ev.Duration)),
    }
    };

We can add the following custom fields for some of the other details of the json data field.

    new CustomColumn("UserName", ev=> ev.Environment.UserName.ToString()),
    new CustomColumn("MachineName", ev=> ev.Environment.MachineName.ToString()),
    new CustomColumn("DomainName", ev=> ev.Environment.DomainName.ToString()),
    new CustomColumn("CallingMethod", ev=> ev.Environment.CallingMethodName.ToString()),
    new CustomColumn("DatabaseName", ev=> ev.GetEntityFrameworkEvent().Database.ToString()),
    

Since the entries of the json content is little bit different in insert and update, I'm still trying to separate data by the action.