MVC Code- or Model First - asp.net-mvc

Question

Most of the tutorials for MVC with Entity Framework are centered around Code-First, where you write classes for generating the model. This gives the advantage of control and Migrations, but I think it lack overview. I would therefore prefer to create the model using the graphical designer, but I cannot see how or if data migrations work in this context. It seems, that when I change the model (with data in the database), all the data is deleted in all tables.
Is there a way around this?
How can I do validation when using Model-First? Partial classes?

Answer 1

you may use the global validation beside mvc validation
example :
public class ValidationCriteria
{
public ValidType Type { get; set; }
public ValidRange Range { get; set; }
public ValidFormat Format { get; set; }
public ValidIsNull IsNull { get; set; }
public ValidCompare Compare { get; set; }
public ValidDB DB { get; set; }
public string Trigger { get; set; }
public Dictionary<string, ValidationCriteria> Before { get; set; }
public string After { get; set; }
public class ValidDB
{
public string functionName { get; set; }
public object[] param { get; set; }
public object functionClass { get; set; }
public string msg { get; set; }
public bool check = false;
}
public class ValidCompare
{
public string first { get; set; }
public string second { get; set; }
public string compareOperator { get; set; }
public string compareValue { get; set; }
public string msg { get; set; }
public bool check = false;
}
public ValidationCriteria()
{
this.Range = new ValidRange();
this.Format = new ValidFormat();
this.IsNull = new ValidIsNull();
this.Type = new ValidType();
this.Compare = new ValidCompare();
this.DB = new ValidDB();
this.Trigger = "blur";
this.Before = new Dictionary<string, ValidationCriteria>();
this.After = "";
}
public class ValidType
{
// checking element is integer.
public bool isInt { get; set; }
// checking element is decimal.
public bool isDecimal { get; set; }
public string msg { get; set; }
public bool check = false;
}
public class ValidRange
{
public long min { get; set; }
public long max { get; set; }
public string msg { get; set; }
public bool check = false;
}
public class ValidFormat
{
public bool isEmail { get; set; }
public string regex { get; set; }
public string msg { get; set; }
public bool check = false;
}
public class ValidIsNull
{
public string nullDefaultVal { get; set; }
public string msg { get; set; }
public bool check = false;
}
}
Meanwhile you may use validation part in your controller
Example :
private bool validateMaintainanceManagement(MaintainanceCRUD.Maintainance model, bool edit = false, bool ServerValidation = true)
{
bool ValidModel = false;
Dictionary<string, ValidationCriteria> validCriteria = new Dictionary<string, ValidationCriteria>();
#region maintainTitle Criteria
ValidationCriteria maintainTitle = new ValidationCriteria();
maintainTitle.IsNull.msg = Resources.Home.ErrmaintainTitle;
maintainTitle.IsNull.check = true;
maintainTitle.IsNull.nullDefaultVal = "-1";
//maintainTitle.Trigger = "change"; // this may trigger if you are using dropdown
validCriteria.Add("maintainTitle", maintainTitle);
#endregion