How Do You Clear an Array at Runtime?

lildaddyblue

Hi all. I have created a Windows application that is linked to a database. (You would think that, if I can do all that, why don't I know this?) (Also note that someone has mentioned to me something about using a 2 dimensional array, although I'm not sure how to do it and is probably a question for another thread.) Anyway, I am using 16 arrays. These arrays hold the primary data for the application. Here are the arrays: double[] billDbl = new double[30], incomeDbl = new double[30]; double[] sda1Dbl = new double[9], sda2Dbl = new double[9]; double[] sda3Dbl = new double[9], cda1Dbl = new double[9]; double[] cda2Dbl = new double[9], cda3Dbl = new double[9]; double[] swa1Dbl = new double[9], swa2Dbl = new double[9]; double[] swa3Dbl = new double[9], cwa1Dbl = new double[9]; double[] cwa2Dbl = new double[9], cwa3Dbl = new double[9]; string[] billDes = new string[30] incomeDes = new string[30]; The index for each array is unique and must also be updated as items are deleted or loaded. For instance, if 3 bills are added, billDbl[0], billDbl[1], and billDbl[2] contain values. If we use the int variable 'b' as the index for billDbl, then 'b' would now have the value of 2. What I'm getting at is that 'b' would have to be set equal to 0, if all array elements were set to 0 (for double arrays) or null (for string arrays). Here are the integer variables for the above arrays: int b = 0, sda1 = 0, sda2 = 0, sda3 = 0, swa1 = 0, swa2 = 0, swa3 = 0; int cda1 = 0, cda2 = 0, cda3 = 0, cwa1 = 0, cwa2 = 0, cwa3 = 0, i = 0; All that being said, I realize that I could clear all the arrays like this: int x = 0; while (x < 30) { billDbl[x] = 0; x = x + 1; } b=0;//Here the integer variable would be set to zero after the array was cleared to prevent any out of range exceptions caused by loops later on, not to mention the fact that if b was still set to 2 it would only allow 27 total bills instead of the 30 possible (lol and that's just a couple of the errors it would cause). All arrays could be cleared in a similar fashion. My question is, (I know you're all saying finally), is there a way that I could set all double array elements to 0 and all string array elements to null when someone clicks on a Menu Item called New Budget without using all those loops? I have seen a method in the msdn library. Here is what it shows: void IList.Clear(); There is also another method there. This is what that one looks like: public static void Clear(Array array, int index, int length); How could I put one of these in my code and actually get it to work? I tried using: IList.Clear(); in my click event, but it wouldn't even bring up clear as an option. (It would bring it up if I used it as its own void. The problem is that I don't know how to connect my click event with that.) I guess the real question is how to actually use this code.

8 Replies

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lildaddyblue21y ago
Actually, you don't even need to put in the word System. Array.Clear(billDbl, 0, billDbl.Length); works the same. The line of code I used in my previous post was the actual creation of the method. The code in this post calls that method and applies it to the billDbl array. As far as creating an array of objects, could you elaborate on that and maybe give an example? My program contains 10,200+ lines of code, so any way(s) to reduce its size and complexity would be greatly appreciated. I have spent about 2 months working on it. I even created an installer for it. It is, however, my first real application, so it probably could have been done more efficiently.
Mykonine21y ago
Looking from a design standpoint, wouldn't it be less confusing if you, instead of using parallel arrays, used an array of objects?
Mykonine21y ago
The call to clear an array should look like this... (The way you do it, the clearing actually does nothing because you call an empty method) System.Array.Clear(myArray, 0, myArray.Length);
lildaddyblue21y ago
I fixed the problem. I'm not sure why this was needed or why it works now, but this cleared things up. public static void Clear(Array array, int index, int length) { } Take away the semi-colon and create an empty block. Like I said, I have no idea why this works... It works fine now, though. Thanks again Simon! Cheers
lildaddyblue21y ago
Thanks for the reply. It looks as if this will work, but it gives me a compile error. I have even created the line: public static void Clear(Array array, int index, int length); When typing Array. it puts the options up and Clear is one of them, so it looks as if this will work... Here is the error it gives: F:\BudgetMain.cs(186): 'Budget_Wizard.BudgetMain.Clear(System.Array, int, int)' must declare a body because it is not marked abstract or extern When reading about this error, one of the lines said this: Abstract property declarations are only permitted in abstract classes (Section 10.1.1.1). Should I create a separate class for this, and, if so, how? Is there a way that I could use the get/set accessors instead?
shimtanny21y ago
Hi Use it the following way: int[] iarr = new int[20]; Array.Clear(iarr, 0, iarr.Length); -> Then the whole array is cleared. simon
lildaddyblue21y ago
This is the method that it shows: public static void Clear(Array array, int index, int length); I think that I have figured out how to set this up, (by adding new code to the auto-generated code), but now I'm wondering this... It seems to be wanting an index. That would indicate that I would need a loop to clear the entire array anyway. :( I suppose I can live with that, but I was hoping there was an easier method than to use 16 loops. Something similar to dataSet.Clear(); would be great. I guess that's what I get for trying to dodge using an ArrayList.
shimtanny21y ago
Hi System.Array doesn't implement the IList interface, therefore IList.Clear() is not available. Most collections (like ArrayList, etc.) implement the IList interface. Your arrays (created like double[] darr = new double[30]) are derived from System.Array. System.Array provides the static method Clear. Here you can find the documentation (msdn) about this method. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemarrayclasscleartopic.asp Simon