how to validate a combobox

Question

2.67/5 (3 votes)

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i have used this method for required field combo box but the problem is. i want to validate combo box with spaces. i dont want user to enter spaces at the start and end of string and i dont want user to enter more than one whitespaces one after the other like adil shaikh how can i achive this?

C#

public bool valcombo()
        {
            if (comboBox1.Text == string.Empty)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

Posted 18-Nov-12 17:57pm

shaikh-adil

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Comments

Sergey Alexandrovich Kryukov 19-Nov-12 0:38am

The statement like

if (something) { return true; } else { return false; }

shows deep confusion about "if" and condition, and, basically, on how to do simple programming. It should be:

return something; //instead!

--SA

Sergey Alexandrovich Kryukov 19-Nov-12 0:41am

Better allow the user to add any number of leading and trailing blank spaces, only, before validation, work with myComboBox.Text.Trim().
--SA

2 solutions

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Subrata.In · Accepted Answer · 2012-11-18T18:33:00

Solution 2

You can try this:

C#

public bool valcombo()
{
   //It will prevent space in begin, End and double space within the text
   if (comboBox1.Text.StartsWith(" ")|| comboBox1.Text.EndsWith(" ")|| comboBox1.Text.Contains("  "))
   {
       return true;
   }
   else
   {
       return false;
   }
}

Posted 18-Nov-12 18:33pm

Subrata.In

Comments

Shmuel Zang 19-Nov-12 0:47am

At first thought, I thought about a Regex. But, your solution is more suited to this case. - My 5.

shaikh-adil 19-Nov-12 0:55am

i had used regex for that.but whitespace regex is too difficult to develop.
but this answer was awsome.
+5
thank you sir

deepak.m.shrma · Accepted Answer · 2012-11-18T22:24:00

Solution 3

You can simply use this.

C#

private Boolean valcombo(){
if ((comboBox1.Text.Length - comboBox1.Text.Trim().Length > 0) ||      

(comboBox1.Text.Trim().Length - comboBox1.Text.Trim().Replace(" ", "").Length > 1)) 
            
return true;
            
else
                
return false;    
        }

input               output

" adil shaikh"      true
"adil shaikh "      true
"adil   shaikh"      true
"adil shaikh"      false

Posted 18-Nov-12 22:24pm

deepak.m.shrma

Updated 19-Nov-12 17:55pm

v3

Comments

shaikh-adil 19-Nov-12 7:02am

you diditn understood my question.
I asked for validation for combo box not the textbox.
So where is the textbox1 and textbox2 comes???

deepak.m.shrma 19-Nov-12 23:56pm

i updated solution now please check. its works same yaar... here its more imp how to deal with string not the element. its works for all element which deals with string :-) hope you will get my point.

shaikh-adil 22-Nov-12 3:44am

nice one but i didint understood what you have done. but it is usefull

sariqkhan 22-Nov-12 3:41am

+5but the what does this means?
comboBox1.Text.Length - comboBox1.Text.Trim().Length > 0)
(comboBox1.Text.Trim().Length - comboBox1.Text.Trim().Replace(" ", "").Length > 1))

deepak.m.shrma 22-Nov-12 5:29am

actually i do not use substring or contain method. i actually use .length property of the string. here in ist lin.
ie.
(comboBox1.Text.Length - comboBox1.Text.Trim().Length > 0)
i checked. whether textbox contain space start and ends of the text.
if text original length - removing start or end space > 0 its mean it contain space either start of the text or at end.

in 2nd line or check.
ie.
comboBox1.Text.Trim().Length - comboBox1.Text.Trim().Replace(" ", "").Length > 1)

i checked that text does not contain more than 2 space between its name and sir name.
simple.