NumericUpDown List and Button List . How to link them ?

Question

Hello , I have a List of Buttons and a List of NumericUpDown. numUpDnList = new List(); btnList = new List(); for ( int i = 0; i { Button btn = new Button(); btn.Location = new Point(121, 275 + i * 19); this .Controls.Add(btn); btnList.Add(btn); NumericUpDown numUpDn = new NumericUpDown(); numUpDn.Location = new System.Drawing.Point(120, 275 + i * 19); // numUpDn.Size = new System.Drawing.Size(50, 20); this .Controls.Add(numUpDn); numUpDnList.Add(numUpDn); } I want to: btnList[i].Click += (se, ev) => { numUpDnList[i].UpButton(); } But it doesn't work : " System.ArgumentOutOfRangeException: 'Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index' "

James Axsom · Answer

Hi Catalin Your problem isn’t occurring in the code you provided to us because the code btnList[i].Click += (se, ev) => { numUpDnList[i].UpButton(); } isn’t present in the flow of execution. Its reasonable to assume that this code is being executed elsewhere in your class. Wherever that is, the value of i representing the btnList index and/or numUpDnList index does not exist. For example, let’s assume maxv is 5. Your program draws 5 buttons and draws 5 UpDownNumber controls. These controls are collected in btnList and numUpDnList respectively. The indexes in each list would be 0, 1, 2, 3, 4 for a total of 5 controls in each List. Next you register each button’s click event to the UpDownNumber’s UpButton method. During registration, using my example of indexes: 0, 1, 2, 3 and 4 the value of i at some point in time during code execution goes below 0 or goes above 4. For example, the value of i changes to -1 or it could change to 5. When that happens, you get System.ArgumentOutOfRangeException. The index goes out range. Within Range - Good btnList[0].Click += (se, ev) => { numUpDnList[0].UpButton(); } btnList[1].Click += (se, ev) => { numUpDnList[1].UpButton(); } btnList[2].Click += (se, ev) => { numUpDnList[2].UpButton(); } btnList[3].Click += (se, ev) => { numUpDnList[3].UpButton(); } btnList[4].Click += (se, ev) => { numUpDnList[4].UpButton(); } Out of Range: Exception - Bad btnList[5].Click += (se, ev) => { numUpDnList[5].UpButton(); } Hope this help you.

Catalin KokoTz · Answer

Hello , first i don't think it matters who is maxv since maxv is the same for both lists but this is the rest of the code : Excel.Application xlApp; Excel.Workbook xlWorkBook; Excel.Worksheet xlWorkSheet; Excel.Range range; int rCnt = 0; xlApp = new Excel.Application(); xlWorkBook = xlApp.Workbooks.Open(@ "D:\pga.xlsx" , 0, true , 5, "" , "" , true , Excel.XlPlatform.xlWindows, "	" , false , false , 0, true , 1, 0); xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1); range = xlWorkSheet.UsedRange; rCnt = range.Rows.Count; int maxv = rCnt - 1; Pret = new int [maxv]; Stock = new int [maxv]; Depozit = new int [maxv]; Produse = new string [maxv]; demovec = new int [maxv]; for ( int i = 0; i { Produse[i] = (xlWorkSheet.Cells[i + 2, 1].value); Pret[i] = Convert.ToInt32(xlWorkSheet.Cells[i + 2, 2].value); Stock[i] = Convert.ToInt32(xlWorkSheet.Cells[i + 2, 3].value); Depozit[i] = Convert.ToInt32(xlWorkSheet.Cells[i + 2, 4].value); } xlWorkBook.Close(); xlApp.Quit(); releaseObject(xlWorkSheet); releaseObject(xlWorkBook); releaseObject(xlApp);

Rajneesh Chaubey · Answer

Hi, This error occurs when you try to access an element of a collection which is outside of its bounds (e.g. element 5 of a 4 element array). Share your implementation details of maxv which your comparing in your for loop with i.