How to change dropdownlist

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I have a dropdown list of date.

when the page load I fill the list -

C#

int endYear = DateTime.Now.Year + 1;
          for (int i = 1; i < 31; i++)
          {
              DDLday.Items.Add(i.ToString());
          }
          for (int i = 1; i < 13; i++)
          {
              DDLmonth.Items.Add(i.ToString());
          }
          for (int i = endYear; i > 1920; i--)
          {
              DDLYear.Items.Add(i.ToString());
          }

and put the date from the database

C#

DateTime bday = DateTime.Parse(currentUser.Date.ToString());
DDLday.SelectedValue = bday.Day.ToString();
DDLmonth.SelectedValue = bday.Month.ToString();
DDLYear.SelectedValue = bday.Year.ToString();

and when I want to edit the date in the data -

C#

Date = DateTime.Parse(DDLday.Text + "/" + DDLmonth.Text + "/" + DDLYear.Text),

but the problem is because I use .selectedvalue the text not changed, how can I edit the date?

What I have tried:

I am beginner and I don't know what to do

Posted 9-Dec-19 11:43am

Member 14683862

Updated 10-Dec-19 9:20am

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Comments

MadMyche 9-Dec-19 17:54pm

Lets start with What Language are you working in?

Member 14683862 10-Dec-19 6:59am

c#

Maciej Los 10-Dec-19 4:12am

Using ToString() method is redundant!
You have to work on proper data types.
Imagine: "2019-12-10" and "2019.12.10" and "2019/12/10" are string representation of dates, accordingly in Polish, German and English notations. They are equal (as a date), but its string representation - NOT!

2 solutions

Solution 1

Please, read my comment to the question first!

Here is an example of what i've stated in the comment.

C#

System.Globalization.CultureInfo[] cis = new System.Globalization.CultureInfo[]
	{
		new System.Globalization.CultureInfo("PL-pl"),
		new System.Globalization.CultureInfo("DE-de"),
		new System.Globalization.CultureInfo("EN-us")
	};
	
DateTime dt = DateTime.Today;
foreach(System.Globalization.CultureInfo ci in cis)
	Console.WriteLine(dt.ToString("d", ci));

As you can see, i'm using one date, but result is:

2019-12-10
10.12.2019
12/10/2019

More:
Standard Date and Time Format Strings | Microsoft Docs[^]
Custom date and time format strings - .NET | Microsoft Docs[^]

Additional note: Do not create a date like this:

C#

DateTime dt = DateTime.Parse(DDLday.Text + "/" + DDLmonth.Text + "/" + DDLYear.Text),

Rather then it, use:

C#

DateTime dt = new DateTime(DDLday.SelectedValue, DDLmonth.SelectedValue, DDLYear.SelectedValue),

Finally, i'd suggest to read this: asp.net - SelectedValue vs SelectedItem.Value of DropDownList - Stack Overflow[^]

Posted 9-Dec-19 22:33pm

Maciej Los

Comments

Member 14683862 10-Dec-19 7:04am

first of all thank you,

but the most question is -
how can i put when the page load DDLday.SelectedValue = 14;
and after the user change the selctedvalue and submit it will change?

Maciej Los 10-Dec-19 11:27am

Try this:

//changing index
DropDownList1.SelectedIndex = DropDownList1.Items.IndexOf(DropDownList1.Items.FindByValue(<value>));
//or
//DropDownList1.SelectedIndex = DropDownList1.Items.IndexOf(DropDownList1.Items.FindByText(<Text>));

//changing value
DropDownList1.Items.FindByText("<Text>").Selected = true ;
//or
//DropDownList1.Items.FindByValue("<value>").Selected = true ;

Member 14683862 10-Dec-19 15:13pm

thank you...

Maciej Los 12-Dec-19 12:56pm

You're very welcome.

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Member 14683862 · Accepted Answer · 2019-12-10T09:21:00

Solution 2

i put in the code

C#

if(!IsPostBack)

Posted 10-Dec-19 9:21am

Member 14683862