handling drop down in asp.net/C#

Question

Hi I have a scenario like this.. In a page I have many dropdown and a single save button.Supposing if user changes 3 values of dropdownand then he clicks save button. 1.A dialog box should appear which confirm that he has changed the value of three dropdowns. How should I achieve this problem?Help me with the code.. Thanks

Kriti · Answer

Hey Niki

Nilanka Dharmadasa · Answer

Hi Swati I changed my code to support a web application. Use it. private int numberofchangeddropdown = 0; private System.Collections.ArrayList dropdowns = new System.Collections.ArrayList(); protected void Page_Load(object sender EventArgs e) { foreach (Control c in this.Controls) { if (c is DropDownList) { DropDownList obj = (DropDownList)c; obj.SelectedIndexChanged += new System.EventHandler(this.Dropdownlist_SelectedIndexChanged); //You bind the same event to all the dropdowns. } } } protected void Dropdownlist_SelectedIndexChanged(object sender EventArgs e) { //You check whether you already counted that dropdown. Otherwise if you change one dropdown two times it will count 2 which is not correct. if (!dropdowns.Contains(sender)) { dropdowns.Add(sender); numberofchangeddropdown++; } } protected void Button1_Click(object sender EventArgs e) { Page.RegisterClientScriptBlock(msg  alert(' You made changes in  + numberofchangeddropdown.ToString() +  dropdowns') ); }

Santhosh N · Answer

Please try code first and let me know...i just tried it in my local and its working..

Kriti · Answer

Hey to reply to urs answer.. I dont know the total number of drop-down to bind it in the code..Its dynamic..A page retrieves the number of drpdown according to some case..

Nilanka Dharmadasa · Answer

Hi swati My code works for any number of dropdowns. You can use it. But please do not forget to tick Do you like this answer checkbox. In my code you have only one event and you bind all the dropdowns to that event. If you download the code from my previous reply it will be easier for you. If you are using a web application replace ComboBox with DropDownList. There will be no other difference. private int numberofchangeddropdown = 0; private ArrayList dropdowns = new ArrayList(); public Form1() { InitializeComponent(); foreach (Control c in this.Controls) { if(c is ComboBox) { ComboBox obj = (ComboBox)c; obj.SelectedIndexChanged += new System.EventHandler(this.comboBox_SelectedIndexChanged); //You bind the same event to all the dropdowns. } } } private void button1_Click(object sender EventArgs e) { MessageBox.Show(You changed + numberofchangeddropdown.ToString() +  dropdowns !); } private void comboBox_SelectedIndexChanged(object sender EventArgs e) { //You check whether you already counted that dropdown. Otherwise if you change one dropdown two times it will count 2 which is not correct. if (!dropdowns.Contains(sender)) { dropdowns.Add(sender); numberofchangeddropdown++; } }

Santhosh N · Answer

If you are having dynamic controls then you can use this .. foreach ( Control c in this .form1.Controls) if (c.GetType().Name == DropDownList ) if ((( DropDownList )c).SelectedIndex != 0) cnt += 1; Page.RegisterClientScriptBlock( msg   alert(' You made changes in  + cnt.ToString() +  dropdowns')  ); cnt = 0;

Kriti · Answer

Hey again to clarify..I have a page which retrieves n number of dropdown .A user can change the value of any number of dropdown(Page is editable)..and same number should appear in the dialog box..whenever he saves changes..

Nilanka Dharmadasa · Answer

Hi Swati It's not difficult. I wrote a small application for you. Download it and check. It supports any number of dropdowns. If my answer helps you please do not forget to tick ' Do you like this answer ' checkbox.

Santhosh N · Answer

Have a global variables for the count and check the count and display the alert.. static int cnt = 0; protected void Page_Load( object sender EventArgs e) { //your page load code.. } protected void Dropdownlist1_SelectedIndexChanged( object sender EventArgs e) { cnt += 1; } protected void Dropdownlist2_SelectedIndexChanged( object sender EventArgs e) { cnt += 1; } protected void Dropdownlist3_SelectedIndexChanged( object sender EventArgs e) { cnt += 1; } protected void Button1_Click( object sender EventArgs e) { Page.RegisterClientScriptBlock( msg   alert(' You made changes in  + cnt.ToString() +  dropdowns')  ); } and this can be customized properly to check if the dropdown is clicked twice by having a seperate variable for each dropdown and check in the button click..

Kriti · Answer

Hey that was my supposition to alter the value of three no. of dropdown..A user can change 'n' no. of dropdown ..and the same should appear in the dialog box...Pls help me with this.. Thanks

Hiren Soni · Answer