CODEWITHSUNDEEP
c#.netstringsubstring
Abdur Rahim
Abdur Rahim

Reputation: 4021

String.Substring(...) Method Gives Exception

I want to keep a string to another string strTotal from a richtextbox. then i want to split it into two SubString like firstPart and secondPart by a middle index say: midIndex.

Then I want to change some value in firsthalf and join with secondhalf. And finally show it to the richTextBox.

For this i used this code:

For my Last debug:

rtxtQueryPan.Text.Length = 53; midIndex = 45;

 //string Totalqueryy = rtxtQueryPan.Text;
 string firstHalf = rtxtQueryPan.Text.Substring(0, midIndex-2); 
 string secondHalf = rtxtQueryPan.Text.Substring((midIndex- 1), (rtxtQueryPan.Text.Length - 1)); // THIS LINE SHOWS ERROR

 string duplicateFirstHalf = firstHalf;
 firstHalf += " " + clColumnNames.Text + ",";
 rtxtQueryPan.Text = firstHalf+secondHalf;

In the 3rd Line of the code says:

Index and length must refer to a location within the string. Parameter name: length

I have checked the length, midIndexvalue etc. But found no clue.

Upvotes: 0

Views: 1088

Answers (3)

David Pfeffer
David Pfeffer

Reputation: 39833

C#'s .Substring function takes a length, not a position as its second argument.

Thus, you probably wanted to write the following code:

rtxtQueryPan.Text.Substring(midIndex-1, (rtxtQueryPan.Text.Length-1) - midIndex);

Also, the length argument is optional, and not something you should provide in your case, as you want the rest of the string included. You can also therefore write:

rtxtQueryPan.Text.Substring(midIndex-1);

Upvotes: 4

MoonKnight
MoonKnight

Reputation: 23833

Substring can only work in the bounds of the string being acted upon. Here, rtxtQueryPan.Text refers to the text in the RichTextBox which is longer that the text currently held in the string. Remember the arguments of Substring are the start position and length.

You want (rtxtQueryPan.Text.Length-1) - midIndex as the second argument.

I hope this helps.

Upvotes: 1

Bored915
Bored915

Reputation: 179

The problem is your grabbing the second string from the half way through and saying i want the entire string. if you use substring the second pramater is the length of your substring. this should fix it. string secondHalf = rtxtQueryPan.Text.Substring((midIndex- 1), (rtxtQueryPan.Text.Length - 1-midIndex));

Upvotes: 1

Related Questions