CODEWITHSUNDEEP
c#asp.netemail
user2931015
user2931015

Reputation: 219

Operator '==' cannot be applied to operands of type 'string' and 'bool'

i try to send mail in asp.net like this

code

     if ( DropDownListcontrol!= null)
                  {

                      if (DropDownListcontrol.SelectedValue == true)
                      {

                          //get Current EMAIL_ID from the DataKey

                          string emailId = 
                      ((Label)Repeater2.Items[i].FindControl("Label2")).Text;
                          //write code to send mail
                          SendEmailUsingGmail(emailId);
                          dt.Clear();
                          dt.Dispose();
                      }
                      else if (DropDownListcontrol.SelectedValue == false)
                      {
                      }
                  }

but here occur in this line 

DropDownListcontrol.SelectedValue == false

ERROR: Operator '==' cannot be applied to operands of type 'string' and 'bool'

how i solve this?

Upvotes: 1

Views: 20294

Answers (5)

Phani
Phani

Reputation: 861

you should have been more specific about what your values in dropdown list are.

anyways, my suggestions:

if values in your dropdown list are "true" and "false" , then you have to use:

if(DropDownListcontrol.SelectedValue == "true")
{

}

if you are just checking whether a user has selected some value in the dropdown list then you have to use:

if(DropdownListControl.SelectedIndex == -1)
{

}

Upvotes: 1

LeeWallen
LeeWallen

Reputation: 98

The DropDownList SelectedValue property is a string, so you won't be able to compare the string to a bool value - which is what the error message is (perhaps not very clearly) saying.

Are you trying to tell if there is a selected value in the DropDownList and, if there is, then you want to perform some action (like send email)?

Or, does the DropDownList contain some value that you want to use to determine if an email should be sent? ie, "true" and "false"?

If you are trying to tell if there is a selected value in the DropDownList, then check to see if the SelectedValue is null. However, it might be that there is always an item selected in the list.

Upvotes: 1

Jeroen Vannevel
Jeroen Vannevel

Reputation: 44439

DropDownListcontrol.SelectedValue

This returns a string. You cannot apply a boolean operator to it. I don't immediatly see the need for an if statement. What is you want to do exactly?

If your values in your dropdownlist are actually "true" and "false", just use a literal string comparison:

if(DropDownListcontrol.SelectedValue == "true")

Upvotes: 2

Mud
Mud

Reputation: 28991

Does the dropdown contain string values representing true/false (e.g. "True", "False")? Then you have to convert them to booleans (see: Boolean.TryParse), or just do a string comparison (e.g. SelectedValue.Equals("True")).

Side note: if you have bool isFubar, you never need to write if (isFubar == true). You can simply write if (isFubar).

Upvotes: 1

hutchonoid
hutchonoid

Reputation: 33306

Change it to this:

DropDownListcontrol.SelectedValue == "true"

Or cast your selected value to a bool.

Upvotes: 2

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