how to check if a string has already been read in C#?

Question

1.00/5 (1 vote)

See more:

C#4.0

I just want to check if a string has already been read in C#. this is for my project

thank you for your answer

Posted 30-Jan-16 16:59pm

Member 11968073

Add a Solution

3 solutions

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)

Dave Kreskowiak · Answer 1 · 2016-01-30T17:07:00

Solution 1

You don't. There is no such thing as "checking to see if a string has been read".

Perhaps you need to provide a LOT more detail on the problem and the code involved.

Posted 30-Jan-16 17:07pm

Dave Kreskowiak

Comments

Member 11968073 30-Jan-16 23:12pm

thank you sir this what i like to do

if(string is equal to name)
{
//do something here
}
else if (string has been read)
{
stop();
}

Dave Kreskowiak 30-Jan-16 23:25pm

Like is said, there is no such thing as "string has been read". Where is this string coming from that you need to track it being "read"? Also, you're still going to have to define what that means.

Member 11968073 30-Jan-16 23:29pm

what i mean is
if string has been already check
then it will stop();

Dave Kreskowiak 30-Jan-16 23:32pm

I think your logic is very wrong. This still doesn't make any sense since you're checking the value of the string in the first if statement. The result of "check if string has already been read' would always be true!

What do you hope to achieve with this? Why are you trying to check for this?

Member 11968073 31-Jan-16 0:09am

this is related to my face recognition project.
what im trying to do is, when the face has been already recognized, i would like to have a message that he/she has been already recognized.

thats all sir

Dave Kreskowiak 31-Jan-16 0:17am

You don't do that by checking to see if a string has been read. You do it by assigning a flag to a face object or some other tracking object. I don't know enough about your code so I can't comment further on it.

Member 11968073 31-Jan-16 0:26am

name = Eigen_Recog.Recognise(result);

if (string.IsNullOrEmpty(name))
{
imageframe.Draw("Unknown", ref font, new Point(facesDetected[i].X - 2, facesDetected[i].Y - 2), new Bgr(Color.Red));
}
else if (!string.IsNullOrEmpty(name))
{
imageframe.Draw(name, ref font, new Point(facesDetected[i].X - 2, facesDetected[i].Y - 2), new Bgr(Color.Red));
db_con.GetFace(name);
label1.Text = name + " attended";
ADD_Face_Found(result, name);
}

this is where my recognition process happens

Dave Kreskowiak 31-Jan-16 0:32am

Uhhh...you don't need the second if statement. The string is either IsNullOrEmpty or it's not.

So you have a library that is doing all the work and all it's returning is a name for the face recognized?

Member 11968073 31-Jan-16 0:43am

yes sir that's correct

Dave Kreskowiak 31-Jan-16 9:33am

Well then, you're going to have a hard time with your requirement. If all you get back is a name, that's the only thing you can track. Hopefully, you don't have more than one face with the same name.

You're going to have to keep a list of names returned and a time at which the face was recognized. That time will server as a timeout so the name can drop off the list after a period so you don't have the name in the list forever while the face is no longer seen. If the person comes back into frame after a short period they won't get added to the list again.

Member 11968073 30-Jan-16 23:34pm

im sorry sir thank you for your expertise.

Peter Leow · Answer 2 · 2016-01-30T17:29:00

Solution 2

Check this out: How to: Compare Strings (C# Programming Guide)[^]

Posted 30-Jan-16 17:29pm

Peter Leow

a_pess · Answer 3 · 2016-01-30T17:42:00

I think you can check if value has been assigned to the string but it is not logic to check if a string has already been read, code in VB.Net and you may convert to C# if it is OK with you

code should looks

VB

Private IsValueAssigned As Boolean
Public ReadOnly Property IsHaveValue As Boolean
    Get
        Return IsValueAssigned
    End Get
End Property

Private stringValue As String
Public Property ValueString As String
    Get
        Return stringValue
    End Get
    Set(value As String)
        stringValue = value
        IsValueAssigned = True
    End Set
End Property