Index was out of range

Question

I'm getting the following message pop up even though the function works:

Index was out of range. Must be non-negative and less than the size of the collection. Parameter name:Index

I think it may be a null issue, but what would be the best way to overcome it on my code below. Basiclly i fill my dataset then databind it to a datagridview, then i hide columns i don't need to be seen in my datagrid, although the datagrid fills fine it throws the above message. my sample code below:

DataSet dsLookup = new DataSet();

dsLookup.ReadXml(response.GetResponseStream());

                            dataGridView1.DataSource = dsLookup.Tables[0];
                            dataGridView1.Columns["StockNumber"].DisplayIndex = 0;
                            dataGridView1.Columns["RegistrationNumber"].DisplayIndex = 1;

                            dataGridView1.Columns[0].Visible = false;
                            dataGridView1.Columns[1].Visible = false;

Vulpes · Answer

In fact here's a better way. Just replace this block of statements: dataGridView1.Columns[21].Visible = false; dataGridView1.Columns[22].Visible = false; dataGridView1.Columns[23].Visible = false; dataGridView1.Columns[24].Visible = false; dataGridView1.Columns[25].Visible = false; dataGridView1.Columns[26].Visible = false; dataGridView1.Columns[27].Visible = false; dataGridView1.Columns[28].Visible = false; dataGridView1.Columns[29].Visible = false; With this one: for(int i = 21; i

Vulpes · Answer

Thought I'd just add that if there's a possibility that the XML file might not contain at least 22 columns then you'll need to do individual 'if' statements on the earlier lines for which Visible is being set to false.

mike Delvotti · Answer

Ooops you posted while i was typing and answered my question once again Thanks Vulpes :)

mike Delvotti · Answer

Yes it has - Thanks vulpes. Can i use that on the other lines as well as a failsafe incase on other returns the lines don't exist either? for instance as below: if (dataGridView1.Columns.Count > 28) dataGridView1.Columns[28].Visible = false; if (dataGridView1.Columns.Count > 29) dataGridView1.Columns[29].Visible = false; so if in future say one of the xml returns only come back with 10 coulmns in theory with that code as above on every line it wouldn't matter is that correct?

Vulpes · Answer

If you replace this line: dataGridView1.Columns[29].Visible = false; with: if (dataGridView1.Columns.Count > 29) dataGridView1.Columns[29].Visible = false; then that should fix it.

mike Delvotti · Answer

Ah yes thanks Vulpes you are indeed correct the fault is thrown on this line: dataGridView1.Columns[29].Visible = false; In that case is there any way to check to see if those columns exist? as some returns may contain column[29]

Vulpes · Answer

I doubt whether this is to do with whether some of the columns in the DGV are null or not. A more likely explanation is that the XML file is such that it's not generating 30 columns of data. If you're not sure you could try commenting out lines starting from the bottom until a point is reached when the exception no longer occurs.

mike Delvotti · Answer

Hi Vulpes yes sorry there is more code the complete example is below: I think the below section here maybe throwing the fault as some of the entries it returns are blank and maybe needs to ignore nulls? dataGridView1.Columns[StockNumber].DisplayIndex = 0; dataGridView1.Columns[RegistrationNumber].DisplayIndex = 1; dataGridView1.Columns[MakeDescription].DisplayIndex = 2; dataGridView1.Columns[ModelDescription].DisplayIndex = 3; dataGridView1.Columns[SpecDescription].DisplayIndex = 4; dataGridView1.Columns[Colour].DisplayIndex = 5; dataGridView1.Columns[BodyStyle].DisplayIndex = 6; dataGridView1.Columns[Transmission].DisplayIndex = 7; dataGridView1.Columns[EngineSize].DisplayIndex = 8; dataGridView1.Columns[FuelType].DisplayIndex = 9; dataGridView1.Columns[Mileage].DisplayIndex = 10; dataGridView1.Columns[RetailPrice].DisplayIndex = 11; The section below here is simply to remove unwanted columns from the grid dataGridView1.Columns[0].Visible = false; dataGridView1.Columns[1].Visible = false; dataGridView1.Columns[2].Visible = false; dataGridView1.Columns[3].Visible = false; dataGridView1.Columns[4].Visible = false; dataGridView1.Columns[6].Visible = false; dataGridView1.Columns[9].Visible = false; dataGridView1.Columns[14].Visible = false; dataGridView1.Columns[21].Visible = false; dataGridView1.Columns[22].Visible = false; dataGridView1.Columns[23].Visible = false; dataGridView1.Columns[24].Visible = false; dataGridView1.Columns[25].Visible = false; dataGridView1.Columns[26].Visible = false; dataGridView1.Columns[27].Visible = false; dataGridView1.Columns[28].Visible = false; dataGridView1.Columns[29].Visible = false;

Vulpes · Answer

Mike I think you'll need to pinpoint the line where the exception is being thrown using the debugger. My suspicion is that it isn't occurring on any of the lines you've shown. On the face of it it could only occur on the last or last but one lines. But there must be at least two columns in the table otherwise the code would not have got through the two lines before those so an index of 0 or 1 can't be out of range.