insert null value into Database when textbox is empty

Question

I use LINQ to Access DB in my Asp.net page.

I have a form with some textbox and a submit button before user see the form all of the textbox be empty with this code:

txtPName.Text =null;
txtPFamily.Text = null;
txtPUsername.Text = null;
txtPPassword.Text = null;

and after click button the values insert in Databse, but if a textbox was empty I want null value insert in database but insert empty in database:

 Users u = new Users()
 {
      FirstName = txtPName.Text,
      LastName = txtPFamily.Text,
      Username = txtPUsername.Text,
      Password = txtPPassword.Text
 };

Just wondering, why do you want it to be null? For me, null means it has never been set, "" means it has been set but left blank intentionally. — user247702
– user247702, Commented Sep 4, 2013 at 7:50

Tim Schmelter · Accepted Answer · 2013-09-04 07:44:59Z

7

You can use the conditional operator. Since Text properties never return null you can safely check if their Length is 0 (text is empty):

Users u = new Users()
{
    FirstName = txtPName.Text.Length == 0 ? null : txtPName.Text,
    LastName = txtPFamily.Text.Length == 0 ? null : txtPFamily.Text,
    Username = txtPUsername.Text.Length == 0 ? null : txtPUsername.Text,
    Password = txtPPassword.Text.Length == 0 ? null : txtPPassword.Text
};

If you also want to treat white-spaces as "empty", use String.IsNullOrWhiteSpace, e.g.:

FirstName = String.IsNullOrWhiteSpace(txtPName.Text) ? null : txtPName.Text

answered Sep 4, 2013 at 7:44

Tim Schmelter

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5 Comments

Oliver Over a year ago

string.IsNullOrWhiteSpace() could be better as it would null whitespace entries.

Tim Schmelter Over a year ago

@Oliver: I have already included string.IsNullOrWhiteSpace in my answer.

R.C Over a year ago

The check added for Whitespaces is fantastic.This helped me avoid posting one question of mine :) . Upvoted.

Silvermind Over a year ago

Assumption is the mother of all.... ;) It feels so unnatural to assume text is not null. Imo the second approach is way better practice.

Tim Schmelter Over a year ago

You can always use string.IsNullOrEmpty or string.IsNullOrWhiteSpace instead. However, it is worth nothing(especially because OP tries to set it to null explitely) that in ASP.NET a text is never null. The pattern is always that string.Empty is returned instead then. This is the shortened source(ILSpy, TextBox.Text-get): if (text != null) { return text; } return string.Empty;

coolprarun · Accepted Answer · 2013-09-04 07:45:56Z

0

You can use the string.IsNullOrEmpty or string.IsNullOrWhiteSpace methods to check your TextBox value.

//This will set a string of your Textbox to either a value (if it has one) or null

string yourValueToPutIntoDatabase = (string.IsNullOrEmpty(yourTextBox.Text)) ? yourTextBox.Text : null;

You could also use it in an if-statement if you are more comfortable :

string valueToPutInDatabase;
if(string.IsNullOrEmpty(yourTextBox.Text))
{
 //Your textbox was empty
 valueToPutInDatabase = null;
}
else
{
 valueToPutInDatabase = yourTextBox.Text;
}

Try this out..

answered Sep 4, 2013 at 7:45

coolprarun

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Comments

Abhijit · Accepted Answer · 2013-09-04 07:50:11Z

0

try this

if(txtPName.Text==""){
u.FirstName =null;
}
if(txtPFamily.Text==""){
u.LastName =null;
}
if(txtPUsername.Text==""){
u.Username =null;
}
if(txtPPassword.Text==""){
u.Password =null;
}

answered Sep 4, 2013 at 7:50

Abhijit

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