how can validate combobox in c#, combobox used datasource

Question

0.00/5 (No votes)

See more:

I have 3 comboboxes

each combobox data binds from another combobox source

for eg.

student type = dayscholar
hostel
---

if i select dayscholar the another combobox shows student name

if i select student name, the third combobox shows student marks

problem is

how to validate combobox (select or not)

i tried selectedindex, selecteditem, text but no use

C#

private void cmbtype_SelectedIndexChanged(object sender, EventArgs e)
      {
          if (cmbtype.Text == string.Empty)
              return;

SQL

//bind name combobox1
         OleDbdatadapter da = new OleDbdatadapter("select name,id from member_master where Subscribe_Type='" + cmbtype.Text.Trim() + "'  order by name", con);

C#

ds = new DataSet();
da.Fill(ds);
cmbname.Items.Insert(0, string.Empty);
cmbname.DataSource = ds.Tables[0];
cmbname.DisplayMember = "name";
cmbname.ValueMember = "id";

C#

}

private void cmbname_SelectedIndexChanged(object sender, EventArgs e)
{
    if (cmbname.SelectedIndex <= 0)
        return;
    gen_table();
}

private void cmbfor_SelectedIndexChanged(object sender, EventArgs e)
{
    if (cmbfor.Text != "")
        gen_table();
}
private void gen_table()
{
    if (cmbtype.SelectedItem == null)
        return;
    //if (comboBox1.SelectedItem     == null)
    //    return;
    //if (comboBox1.SelectedValue  == null)
    //    return;
    //if (comboBox1.Text  == null)
    //    return;
    if (cmbname.SelectedIndex == 0)
        return;

}
}

Posted 7-Mar-14 0:10am

Arun_Ramasamy

Updated 7-Mar-14 0:52am

v3

Add a Solution

Comments

Amalraj Ramesh 7-Mar-14 6:20am

if you bind the combo box properly
selected value defiantly will work
For better solution post your code logic

Arun_Ramasamy 7-Mar-14 7:53am

Thank u i follow tommie tolmay416

[no name] 7-Mar-14 6:23am

what have you tried for combobox validation yet if you will share it then anyone can help you.

Arun_Ramasamy 7-Mar-14 7:54am

thank u i follow tommie tolmay416

ZurdoDev 7-Mar-14 6:36am

Why won't selectedindex work?

Arun_Ramasamy 7-Mar-14 7:54am

thank u

Vedat Ozan Oner 7-Mar-14 7:06am

what is the problem exactly? what do you intend to do at which point? what do you get?

Arun_Ramasamy 7-Mar-14 7:54am

thank u i follow tommie tolmay416

2 solutions

Solution 2

C#

private void cmbtype_SelectedIndexChanged(object sender, EventArgs e)
        {
              //bind name combobox1
            OleDbDataAdapter da = new OleDbDataAdapter("select name,id from member_master where Subscribe_Type='" + cmbtype.Text.Trim() + "'  order by name", con);
            ds = new DataSet();
            da.Fill(ds);
            cmbname.Items.Insert(0, string.Empty);
            cmbname.DataSource = ds.Tables[0];
            cmbname.DisplayMember = "name";
            cmbname.ValueMember = "id";
            cmbname.SelectedIndex = -1;
}

   private void cmbname_SelectedIndexChanged(object sender, EventArgs e)
        {


            /// Check If combobox text is selected

            if (!string.IsNullOrWhiteSpace(cmbname.Text))
{   /////
            return;
            gen_table();
        
}  /////

your code should be inbetween the brackets.

Posted 7-Mar-14 1:39am

Dr Drastic

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Dr Drastic · Accepted Answer · 2014-03-07T01:00:00

Solution 1

try this.

Please remember to rate my answer.

/// Check If combobox text is selected

if (!string.IsNullOrWhiteSpace(cmbtype.Text))

{

{

Posted 7-Mar-14 1:00am

Dr Drastic

Comments

Arun_Ramasamy 7-Mar-14 7:20am

private void cmbtype_SelectedIndexChanged(object sender, EventArgs e)
{
//bind name combobox1
OleDbDataAdapter da = new OleDbDataAdapter("select name,id from member_master where Subscribe_Type='" + cmbtype.Text.Trim() + "' order by name", con);
ds = new DataSet();
da.Fill(ds);
cmbname.Items.Insert(0, string.Empty);
cmbname.DataSource = ds.Tables[0];
cmbname.DisplayMember = "name";
cmbname.ValueMember = "id";
cmbname.SelectedIndex = -1;
}

private void cmbname_SelectedIndexChanged(object sender, EventArgs e)
{

/// Check If combobox text is selected

if (!string.IsNullOrWhiteSpace(cmbname.Text))
return;
gen_table();
}

return not work properly,

Arun_Ramasamy 7-Mar-14 7:53am

thanku so much

Dr Drastic 8-Mar-14 4:15am

My Pleasure!!!