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get value from data table specific cell and output to textbox

trying to get a value from a data table, and output its contents to a textbox. seems im nearly there but for some reason studio doesnt like dt.rows[][];
ive seen multiple examples online in this format, but i get error CS002, cannot apply indexing with [] to an expression of type 'DataGridViewRow'.
im trying to locate the current row, and i can figure out the column either by putting an index number or by using the name of the column if that works better.
here is datatable_selectionChanged
private void dt_SelectionChanged(object sender, EventArgs e)
{
int row = dt.CurrentCell.RowIndex;
int col = dt.CurrentCell.ColumnIndex;
textBox1.Text = Convert.ToString(row);
textBox2.Text = Convert.ToString(col);
}
here is my mainform_load
private void mainForm_Load(object sender, EventArgs e)
{
string file = #"C:\Users\User\OneDrive - Motion Controls Robotics, Inc\Desktop\test inventory\TIS.xlsm"; //variable for the Excel File Location
DataTable dt = new DataTable(); //container for our excel data
DataRow row;
try
{
//Create Object for Microsoft.Office.Interop.Excel that will be use to read excel file
Microsoft.Office.Interop.Excel.Application excelApp = new Microsoft.Office.Interop.Excel.Application();
Microsoft.Office.Interop.Excel.Workbook excelWorkbook = excelApp.Workbooks.Open(file);
Microsoft.Office.Interop.Excel._Worksheet excelWorksheet = excelWorkbook.Sheets[1];
Microsoft.Office.Interop.Excel.Range excelRange = excelWorksheet.UsedRange;
int rowCount = excelRange.Rows.Count; //get row count of excel data
int colCount = excelRange.Columns.Count;//number of columns to display
//Get the first Column of excel file which is the Column Name
for (int i = 2; i <= rowCount;)
{
for (int j = 1; j <= colCount; j++)
{
dt.Columns.Add(excelRange.Cells[i, j].Value2.ToString());
}
break;
}
//Get Row Data of Excel
int rowCounter; //This variable is used for row index number
for (int i = 3; i <= rowCount; i++) //Loop for available row of excel data
{
row = dt.NewRow(); //assign new row to DataTable
rowCounter = 0;
for (int j = 1; j <= colCount; j++) //Loop for available column of excel data
{
//check if cell is empty
if (excelRange.Cells[i, j] != null && excelRange.Cells[i, j].Value2 != null)
{
row[rowCounter] = excelRange.Cells[i, j].Value2.ToString();
}
else
{
excelRange.Cells[i, j].value2 = "Empty";
//row[i] = "";
}
rowCounter++;
}
dt.Rows.Add(row); //add row to DataTable
}
this.dt.DataSource = dt; //assign DataTable as Datasource for DataGridview
//close and clean excel process
GC.Collect();
GC.WaitForPendingFinalizers();
Marshal.ReleaseComObject(excelRange);
Marshal.ReleaseComObject(excelWorksheet);
//quit apps
excelWorkbook.Close();
Marshal.ReleaseComObject(excelWorkbook);
excelApp.Quit();
Marshal.ReleaseComObject(excelApp);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}

How to copy data from one column to another at the same datatable in c#

I have a datatable filled with information from an excel file. I have more than four columns but to bring an example I'm writing just four of them. I have to write a program in which if the value of the cell in the column C is 0, then I have to copy column B to column A. If the value of the cell in column C is > 0 then i have to copy the column B to A and should add another row in which i have to copy the value of the column C to A.
What i have till now is
for (int r = 2; r <= ws.UsedRange.Rows.Count; r++)
{ if (ws.UsedRange.Cells[r, 3].Text == "0")
{
DataRow row = dt.NewRow();
for (int c = 1; c < ws.UsedRange.Columns.Count; c++)
{
string cell = ws.Cells[r, c].Text;
row[c - 1] = cell;
}
}
So my questions are:
How can i copy a column to another in the same datatable? Copy B to A.
How can i add another row and copy the value of C to A only for that row?
Here is the full code:
public DataTable ReadExcel2(string file)
{
ExcelI.Application app = new ExcelI.Application(); //create an excel instance
ExcelI.Workbook wb = app.Workbooks.Open(file, ReadOnly: true); //open a file
ExcelI.Worksheet ws = wb.Worksheets[1]; //choose a sheet. The firt one
var rng = ws.UsedRange;
//takes the index of the columns that are going to be filtered
int service = ColumnIndexByName(ws.Cells[1, 1].EntireRow, "Service");
int status = ColumnIndexByName(ws.Cells[1, 1].EntireRow, "Status");
int code = ColumnIndexByName(ws.Cells[1, 1].EntireRow, "Code");
DataTable dt = new DataTable();
dt.Columns.Add("A", typeof(string));
for (int c = 1; c < ws.UsedRange.Columns.Count; c++)
{
string colName = ws.Cells[1, c].Text;
int i = 2;
while (dt.Columns.Contains(colName))
{
colName = ws.Cells[1, c].Text + "{" + i.ToString() + "}";
i++;
}
dt.Columns.Add(colName);
}
//do a loop to delete the rows that we dont need
for (int r = 2; r <= ws.UsedRange.Rows.Count; r++)
{
if (ws.UsedRange.Cells[r, 3].Text == "0")
{
DataRow row = dt.NewRow();
for (int c = 1; c < ws.UsedRange.Columns.Count; c++)
{
string cell = ws.Cells[r, c].Text;
row[c - 1] = cell;
}
dt.Rows.Add(row);
row["A"] = row["C"];
}
}
//Close the file
wb.Close();
//release the excel objects from use
Marshal.ReleaseComObject(wb);
Marshal.ReleaseComObject(ws);
//take the id of excel process
int pid = app.PID();
app.Quit();
StartProc("taskkill", $"/f /pid {pid}");
return dt;
}

To add row use dt.Rows.Add(row);, about "copy the column B to A" you mean copy value , just assign row[0] = row[2];, by the way , your example missing a bracket.
I think you should review your code according to conditions in your question, and you can do it yourself as well. Just pay attention to condition you wrote in question and conditional operator you checked in the code.

How to remove a column from excel sheet in epplus

I'm using csharp to insert data into excel sheet into 7 columns. The interface of this program will allow users to select 7 checkboxes. If they select all 7, all the 7 columns in spreadhseet will have data, if they select one checkbox then only one column will have data. I have got a for loop which will check if data is there, if no data exists, I want to remove that column in epplus. Here's a previous discussion on this topic
How can I delete a Column of XLSX file with EPPlus in web app
It's quiet old so I just wanna check if there's a way to do this.
Or, is there a way to cast epplus excel sheet to microsoft interop excel sheet and perform some operations.
Currently, I've code like this:
for(int j=1; j <= 9; j++) //looping through columns
{
int flag = 0;
for(int i = 3; i <= 10; i++) // looping through rows
{
if(worksheet.cells[i, j].Text != "")
{
flag ++;
}
}
if (flag == 0)
{
worksheet.column[j].hidden = true; // hiding the columns- want to remove it
}
}
Can we do something like:
Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application();
xlApp = worksheet; (where worksheet is epplus worksheet)

Are you using EPPlus 4? The ability to do column inserts and deletion was added with the new Cell store model they implemented. So you can now do something like this:
[TestMethod]
public void DeleteColumn_Test()
{
//http://stackoverflow.com/questions/28359165/how-to-remove-a-column-from-excel-sheet-in-epplus
var existingFile = new FileInfo(#"c:\temp\temp.xlsx");
if (existingFile.Exists)
existingFile.Delete();
//Throw in some data
var datatable = new DataTable("tblData");
datatable.Columns.Add(new DataColumn("Col1"));
datatable.Columns.Add(new DataColumn("Col2"));
datatable.Columns.Add(new DataColumn("Col3"));
for (var i = 0; i < 20; i++)
{
var row = datatable.NewRow();
row["Col1"] = "Col1 Row" + i;
row["Col2"] = "Col2 Row" + i;
row["Col3"] = "Col3 Row" + i;
datatable.Rows.Add(row);
}
using (var pack = new ExcelPackage(existingFile))
{
var ws = pack.Workbook.Worksheets.Add("Content");
ws.Cells.LoadFromDataTable(datatable, true);
ws.DeleteColumn(2);
pack.SaveAs(existingFile);
}
}

Fastest way to drop a DataSet into a worksheet

A rather higeisch dataset with 16000 x 12 entries needs to be dumped into a worksheet.
I use the following function now:
for (int r = 0; r < dt.Rows.Count; ++r)
{
for (int c = 0; c < dt.Columns.Count; ++c)
{
worksheet.Cells[c + 1][r + 1] = dt.Rows[r][c].ToString();
}
}
I rediced the example to the center piece
Here is what i implemented after reading the suggestion from Dave Zych.
This works great.
private static void AppendWorkSheet(Excel.Workbook workbook, DataSet data, String tableName)
{
Excel.Worksheet worksheet;
if (UsedSheets == 0) worksheet = workbook.Worksheets[1];
else worksheet = workbook.Worksheets.Add();
UsedSheets++;
DataTable dt = data.Tables[0];
var valuesArray = new object[dt.Rows.Count, dt.Columns.Count];
for (int r = 0; r < dt.Rows.Count; ++r)
{
for (int c = 0; c < dt.Columns.Count; ++c)
{
valuesArray[r, c] = dt.Rows[r][c].ToString();
}
}
Excel.Range c1 = (Excel.Range)worksheet.Cells[1, 1];
Excel.Range c2 = (Excel.Range)worksheet.Cells[dt.Rows.Count, dt.Columns.Count];
Excel.Range range = worksheet.get_Range(c1, c2);
range.Cells.Value2 = valuesArray;
worksheet.Name = tableName;
}

Build a 2D array of your values from your DataSet, and then you can set a range of values in Excel to the values of the array.
object valuesArray = new object[dataTable.Rows.Count, dataTable.Columns.Count];
for(int i = 0; i < dt.Rows.Count; i++)
{
//If you know the number of columns you have, you can specify them this way
//Otherwise use an inner for loop on columns
valuesArray[i, 0] = dt.Rows[i]["ColumnName"].ToString();
valuesArray[i, 1] = dt.Rows[i]["ColumnName2"].ToString();
...
}
//Calculate the second column value by the number of columns in your dataset
//"O" is just an example in this case
//Also note: Excel is 1 based index
var sheetRange = worksheet.get_Range("A2:O2",
string.Format("A{0}:O{0}", dt.Rows.Count + 1));
sheetRange.Cells.Value2 = valuesArray;
This is much, much faster than looping and setting each cell individually. If you're setting each cell individually, you have to talk to Excel through COM (for lack of a better phrase) for each cell (which in your case is ~192,000 times), which is incredibly slow. Looping, building your array and only talking to Excel once removes much of that overhead.

How to solve Unable to cast object of type 'System.Data.DataView' to type 'System.Data.DataTable' ERROR

i have Devxpress GridControl on the form,
and i want to send data on this grid to excel.
and i dont want to do this with ExportToExcel method
i have googled and found this code
but this code is for DataGrid control of .Net
and it gives an error when it tries to convert
DevExpress.XtraGrid.Views.Grid.GridView to System.Data.DataView
here is the code
public string LastCoulmLetter(int coulmnCount)
{
string finalColLetter = string.Empty;
string colCharset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int colCharsetLen = colCharset.Length;
if (coulmnCount > colCharsetLen)
{
finalColLetter = colCharset.Substring(
(coulmnCount - 1) / colCharsetLen - 1, 1);
}
finalColLetter += colCharset.Substring(
(coulmnCount - 1) % colCharsetLen, 1);
return finalColLetter;
}
public void FromGridToExcel()
{
if (gridView1.RowCount <= 0)
return;
Excel.Application xls = new Excel.Application();
Excel.Workbook wb;
Excel.Worksheet sheet;
object SalakObje = System.Reflection.Missing.Value;
wb = xls.Workbooks.Add(SalakObje);
sheet = (Excel.Worksheet)wb.ActiveSheet;
sheet.Name = "Result";
xls.Visible = true;
DataTable dt = (DataTable)gridView1.DataSource; // Error comes in here
// Copy the DataTable to an object array
object[,] rawData = new object[dt.Rows.Count + 1, dt.Columns.Count];
// Copy the column names to the first row of the object array
for (int col = 0; col < dt.Columns.Count; col++)
{
rawData[0, col] = dt.Columns[col].ColumnName;
}
// Copy the values to the object array
for (int col = 0; col < dt.Columns.Count; col++)
{
for (int row = 0; row < dt.Rows.Count; row++)
{
rawData[row + 1, col] = dt.Rows[row].ItemArray[col];
}
}
// Fast data export to Excel
string excelRange = string.Format("A1:{0}{1}",LastCoulmLetter(dt.Columns.Count), dt.Rows.Count + 1);
sheet.get_Range(excelRange, Type.Missing).Value2 = rawData;
sheet.get_Range(excelRange).Columns.AutoFit();
}
So what is the problem and how to fix it

The problem appears to be that your DataSource is a DataView, not a DataTable.
Some options:
Cast it to a DataView if you want to use the same filters:
DataView dv = (DataView)gridView1.DataSource;
Use the .Table property to get the source table if you want the raw data:
DataTable dt = ((DataView)gridView1.DataSource).Table;

Try this instead:
DataTable dt = ((DataView)gridView1.DataSource).Table;