Develop Reference

How to add rows from one datagridview to another empty datagridview by some conditional in c#

I'm using visual studio 2017, C#, Windows Forms to create an index for words in a list of sentences.
I have two datagridview:
dataGridView2: This grid has a single column where each row contains a worded sentence.
dGvTopics: This grid has one column for every word that is repeated in the first sentence (first row) in dataGridView2, the column header text is the word.
Goal: I want to click button to categorize, inserting a row in dGvTopics for each row in dataGridView2 (sentences), place a copy of the sentence as the value for that column if the sentence contains the column header text.
My Code is:
private void btnClassify_Click(object sender, EventArgs e)
{
for (int i = 0; i < dGvTopics.Columns.Count; i++)
{
if (dataGridView2.Rows[i].Cells[0].Value.ToString().Contains(dGvTopics.Columns[i].HeaderText))
{
this.dGvTopics.Rows.Add();
this.dGvTopics.Rows[i].Cells[i].Value = dataGridView2.Rows[i].Cells[0].Value;
}
}
}

We can discuss later why you are doing this at all, there are easier ways :)
You need to understand that there are two dimensions to iterate here, the rows in dataGridView2 and the columns in dGvTopics, this means you will need two looping statements, not just one.
Your current code is looping through the Rows in dataGridView2 but only for the number of columns that are in dGvTopics which is a bit confusing.
PRO TIP: Don't use arbitrary single character variable names that have no meaning. Yes i is ubiquitously used to represent index in code you will find around the web, that doesn't mean it is good practice. i should be reserved for lazy programming where there is a single, single dimension array that you are iterating over, in your example there are 4 different levels of arrays that you accessing, the meaning of i is now ambiguous.
Instead of i, use a meaningful variable name like columnIndex or topicIndex. That way when each line is reviewed in isolation, the code is more self documenting. I would even accept t or c in this code, taking the first initial from the conceptual variable meaning will help spot common errors where the wrong indexer is used for the wrong array.
Yes this make the code wordy and long, but we're not constrained by memory space in the same way as our developer ancestors, this doesn't change the size of the final executable, strive to make your code self-documenting.
If you are programming in a code-memory-constrained environment, like for micro-controllers, or tiny chipsets, then still use meaningful short variables, not arbitrarily selected characters.
Applying the above recommendation highlights this first issue:
for (int columnIndex = 0; columnIndex < dGvTopics.Columns.Count; columnIndex ++)
{
if (dataGridView2.Rows[columnIndex].Cells[0].Value.ToString().Contains(dGvTopics.Columns[columnIndex].HeaderText))
{
this.dGvTopics.Rows.Add();
this.dGvTopics.Rows[columnIndex].Cells[columnIndex].Value = dataGridView2.Rows[columnIndex].Cells[0].Value;
}
}
Now we can see that each iteration is moving down the rows, but across the cells at the same rate, meaning that only the cells in a diagonal formation will even be compared and have a value.
The next issue is that because you are only creating a row when the comparison returns true, this means that the rows in dGvTopics might be less than you are expecting, which means less than the value of i (or columnIndex) which will raise an IndexOutOfRangeException the next successful iteration after any comparison that fails.
You can avoid this problem by iterating over the rows and columns separately and adding one row in dGvTopics for every row in dataGridView2.
We can also make the code clearer by saving a reference to the currentSentence rather than referencing the sentence through the array indexers.
private void btnClassify_Click(object sender, EventArgs e)
{
// remove any existing rows, we will reprocess all records.
this.dGvTopics.Rows.Clear();
// Iterate over the rows in the list of sentences.
for (int rowIndex = 0; rowIndex < dataGridView2.Rows.Count; rowIndex ++)
{
// Create one topic row for every sentence
// row index will always be valid now.
this.dGvTopics.Rows.Add();
// save the sentence value to simplify the comparison code.
string currentSentence = dataGridView2.Rows[rowIndex].Cells[0].Value.ToString();
// iterate over the columns in the topics grid
for (int columnIndex = 0; columnIndex < dGvTopics.Columns.Count; columnIndex ++)
{
if (currentSentence.Contains(dGvTopics.Columns[columnIndex].HeaderText))
{
this.dGvTopics.Rows[rowIndex].Cells[columnIndex].Value = currentSentence;
}
}
}
}
It's not easy to comprehend why you want to do this or how this information will be used. In general for manipulating values in cells we generally recommend that databinding techniques are used instead, that way you do not access rows and cells anymore or but the underlying objects that they represent.
demonstrating this is outside of the scope of this question, but it's an avenue worth researching when you have time.
In solutions like this where there are two grids that represent the same logical component, (in this case each row in each grid represents the same sentence value) the underlying dataobject might be a single list, where one property on the object is the sentence and each topic column is a property on the same object.
Importantly, using databinding means that the next process that needs to use the information that you have displayed or edited in the grids can do so without access to or knowledge about the grids at all... Something to think about ;)
Update
This code may result in many empty cells in the topics grid. We could instead only add rows as they are needed, but to do this will require a lot more effort.
NOTE: Grids render all the cells for each row, In the last couple of rows, there may still be empty cells if at least one of the cells for that row has a value.
private void btnClassify_Click(object sender, EventArgs e)
{
// remove any existing rows, we will reprocess all records.
this.dGvTopics.Rows.Clear();
// Iterate over the rows in the list of sentences.
for (int rowIndex = 0; rowIndex < dataGridView2.Rows.Count; rowIndex ++)
{
// save the sentence value to simplify the comparison code.
string currentSentence = dataGridView2.Rows[rowIndex].Cells[0].Value.ToString();
// iterate over the columns in the topics grid
for (int columnIndex = 0; columnIndex < dGvTopics.Columns.Count; columnIndex ++)
{
if (currentSentence.Contains(dGvTopics.Columns[columnIndex].HeaderText))
{
// first we need to know what row index to add this value into
// that involves another iteration, we could store last index in another structure to make this quicker, but here we will do it from first principals.
bool inserted = false;
for(int lookupRow = 0; lookupRow < this.dGvTopics.Rows.Count; lookupRow ++)
{
// find the first row with a null cell;
if(this.dGvTopics.Rows[columnIndex].Value == null)
{
this.dGvTopics.Rows[lookupRow].Cells[columnIndex].Value = currentSentence;
inserted = true;
break;
}
}
if(!inserted)
{
this.dGvTopics.Rows.Add();
this.dGvTopics.Rows[this.dGvTopics.Rows.Count-1].Cells[columnIndex].Value = currentSentence;
}
}
}
}
}

Many thanks to Mr Chris Schaller,
According to his description, the final code changed as follows after compiling:
private void btnClassify_Click(object sender, EventArgs e)
{
// remove any existing rows, we will reprocess all records.
this.dGvTopics.Rows.Clear();
// Iterate over the rows in the list of sentences.
for (int rowIndex = 0; rowIndex < dataGridView2.Rows.Count; rowIndex++)
{
// save the sentence value to simplify the comparison code.
string currentSentence = dataGridView2.Rows[rowIndex].Cells[0].Value.ToString();
// iterate over the columns in the topics grid
for (int columnIndex = 0; columnIndex < dGvTopics.Columns.Count; columnIndex++)
{
if (currentSentence.Contains(dGvTopics.Columns[columnIndex].HeaderText))
{
// first we need to know what row index to add this value into
// that involves another iteration, we could store last index in another structure to make this quicker, but here we will do it from first principals.
bool inserted = false;
for (int lookupRow = 0; lookupRow < this.dGvTopics.Rows.Count; lookupRow++)
{
// find the first row with a null cell;
if (this.dGvTopics.Rows[lookupRow].Cells[columnIndex].Value == null)
{
this.dGvTopics.Rows[lookupRow].Cells[columnIndex].Value = currentSentence;
inserted = true;
break;
}
}
if (!inserted)
{
this.dGvTopics.Rows.Add();
this.dGvTopics.Rows[this.dGvTopics.Rows.Count - 1].Cells[columnIndex].Value = currentSentence;
}
}
}
}
}

how can i calculated values after Worksheet.Calculate()?

i tried Trial version of Gembox.SpreadSheet.
when i Get Cells[,].value by for() or Foreach().
so i think after Calculate() & get Cell[].value, but that way just take same time,too.
it take re-Calculate when i Get Cell[].value.
workSheet.Calcuate(); <- after this, values are Calculated, am i right?
for( int i =0; i <worksheet.GetUsedCellRange(true).LastRowIndex+1;++i)
{
~~~~for Iteration~~~
var value = workSheet.Cells[i,j].Value; <- re-Calcuate value(?)
}
so here is a Question.
Can i Get calculated values? or you guys know pre-Calculate function or Get more Speed?

Unfortunate, I'm not sure what exactly you're asking, can you please try reformulating your question a bit so that it's easier to understand it?
Nevertheless, here is some information which I hope you'll find useful.
To iterate through all cells, you should use one of the following:
1.
foreach (ExcelRow row in workSheet.Rows)
{
foreach (ExcelCell cell in row.AllocatedCells)
{
var value = cell.Value;
// ...
}
}
2.
for (CellRangeEnumerator enumerator = workSheet.Cells.GetReadEnumerator(); enumerator.MoveNext(); )
{
ExcelCell cell = enumerator.Current;
var value = cell.Value;
// ...
}
3.
for (int r = 0, rCount = workSheet.Rows.Count; r < rCount; ++r)
{
for (int c = 0, cCount = workSheet.CalculateMaxUsedColumns(); c < cCount; ++c)
{
var value = workSheet.Cells[r, c].Value;
// ...
}
}
I believe all of them will have pretty much the same performances.
However, depending on the spreadsheet's content this last one could end up a bit slower. This is because it does not exclusively iterate only through allocated cells.
So for instance, let say you have a spreadsheet which has 2 rows. The first row is empty, it has no data, and the second row has 3 cells. Now if you use 1. or 2. approach then you will iterate only through those 3 cells in the second row, but if you use 3. approach then you will iterate through 3 cells in the first row (which previously were not allocated and now they are because we accessed them) and then through 3 cells in the second row.
Now regarding the calculation, note that when you save the file with some Excel application it will save the last calculated formula values in it. In this case you don't have to call Calculate method because you already have the required values in cells.
You should call Calculate method when you need to update, re-calculate the formulas in your spreadsheet, for instance after you have added or modified some cell values.
Last, regarding your question again it is hard to understand it, but nevertheless:
Can i Get calculated values?
Yes, that line of code var value = workSheet.Cells[i,j].Value; should give you the calculated value because you used Calculate method before it. However, if you have formulas that are currently not supported by GemBox.Spreadsheet's calculation engine then it will not be able to calculate the value. You can find a list of currently supported Excel formula functions here.
or you guys know pre-Calculate function or Get more Speed?
I don't know what "pre-Calculate function" means and for speed please refer to first part of this answer.

C# - DataGridView - Breaking out of for loop without being told to

I have the following code:
for (int i = 0; i < COLUMNS.Count; i++)
{
DataGridViewColumn column = new DataGridViewColumn()
{
Name = COLUMNS.ElementAt(i).Key,
HeaderText = COLUMNS.ElementAt(i).Value,
Width = 60
};
operationsDataGridView.Columns.Add(column);
}
I hope it's clear enough, I'm looping through a Dictionary of Column Name and Column Headers, and adding them as DataGridViewColumn instances to the DataGridView.
However, the program is looping only once, when it should loop 9 times (I've already debugged it, and COLUMNS.Count is, in fact, 9)
Therefore, only the first column is added, as it can be seen in the image:
As for the debugging output, these strange messages appear:
I'm sure it has something to do with this problem.
Interesting Fact!
If I change my code to:
for (int i = 0; i < COLUMNS.Count; i++)
{
operationsDataGridView.Columns.Add(COLUMNS.ElementAt(i).Key,
COLUMNS.ElementAt(i).Value);
}
(Which I think, is esentially the same), the program works fine!!

I was able to reproduce this error on my end, but I was getting an exception as well about "At least one of the DataGridView control's columns has no cell template."
If you change your loop to DataGridViewColumn column = new DataGridViewTextBoxColumn() it will probably work (fixed it on my end at least). Looks like the .add method with the two parameters defaults to this type of column.

How to put array into excel range

I know how to write single cell into excel but when im trying it on array excel sheet is filling with only last value
this is my range
Excel.Range ServiceName = (Excel.Range)_sheet.get_Range(_sheet.Cells[38, "B"] as Excel.Range, _sheet.Cells[45, "B"] as Excel.Range);
_ServiceName is List which contains 1,2,3,4,5,6
for (int i = 0; i < _ServiceName.Count; i++)
{
ServiceNameArray[0, i] = _ServiceName[i];
}
this i my trying to write into excel but as i said it there is only last item (6) in excel book
for (int i = 0; i < _ServiceName.Count; i++)
{
ServiceName.set_Value(Type.Missing, ServiceNameArray[0,i]);
}
does anyone have an idea?

Davide Piras is right. And you're doing a few other strange things there, I can elaborate by request.
For now I just want to point out that you can directly assign the .Value property of a Range to an array:
ServiceName.Value2 = _ServiceName.toArray();
This is much, much faster for bigger amounts of data.
(Side note: If you want to do the same with Formulas, for some strange reason you have to take an extra step (doubling the time):
range.Formula = array;
range.Formula = range.Formula;
unless there is a better way I don't know about yet.)

I see you looping on the ServiceName array to get all values one after the other but not see you changing the focused cell inside the cellrange at every loop iteration. Of course, I would say, you see only the last value, because you are writing all values one over the other always in the same place.

Iterating over ListView data

I have a ListView which is bound to a DataTable. I would like to iterate over the DataTable's rows and access their data. I figured, to do this, I would simply iterate over the ListViewDataItems in the ListView. To test that I am properly accessing the data, I tried the following code, which should simply print the string at column 0 for each row.
for (int i = 0; i < MyListView.Items.Count; i++)
{
ListViewDataItem item = MyListView.Items[i];
DataRow row = (DataRow) item.DataItem;
Response.Write(row[0]);
}
However, nothing is printed. To verify that the ListView is not empty (which it shouldn't be as the data is properly rendered on my aspx page), I tried this:
Response.Write(MyListView.Items.Count);
This prints the number 16, which is correct as there are 16 rows in my ListView. I'm guessing I'm just not accessing the data correctly. I'd appreciate some insight on this.

The best way is to stop on breakpoint (at line DataRow row = (DataRow) item.DataItem;) and simply to check what you have .
for example like here :http://msdn.microsoft.com/en-us/library/ms173083(v=VS.90).aspx

I decided the best solution was to just iterate over the data directly in the DataTable rather than the ListViewDataItems.
for (int i = 0; i < myTable.Rows.Count; i++)
{
for (int j = 0; j < myTable.Columns.Count; j++)
{
object data = data.Rows[i][j];
// do stuff with data
}
}

For anyone still seeking the correct answer to this question, the following code will work (VB.NET):
Dim di as ListViewDataItem
For Each di in MyListView.Items
Response.Write(CType(di.FindControl("ExampleLabel"), Label).Text)
Next
Just substitute the Response.Write line with whatever you wanted to do to each list item. The example line is looking for a control called 'ExampleLabel', casts it back to a label then writes the text value onto the page.
Easily adapted to C# for anyone proficient (not I alas).