Develop Reference

C# memory leak using exel and interop COM

UPDATED 3/12/20. I am struggling with a problem where the Excel application is not releasing following my function call below. I'm not sure what references I'm screwing up but I assume I'm somehow leaving a reference to the application because I see multiple Excel processes in my task manager as the program runs, not to mention large amounts of memory use that don't improve with GC. Thoughts?
static void ParseExcel(string file, SqlConnection conn)
{
Excel.Application xlApp = new Excel.Application();
Excel.Workbook xlWorkbook = xlApp.Workbooks.Open(file);
Excel._Worksheet xlWorksheet = xlWorkbook.Sheets[1];
Excel.Range rng = xlWorksheet.UsedRange;
SqlCommand cmd = conn.CreateCommand();
double colCount = rng.Columns.Count;
double rowCount = rng.Rows.Count;
//iterate over the rows and columns
//start on row 2 since row 1 is column headers
for (int i = 2; i <= rowCount; i++)
{
string companyName = "";
for (int j = 1; j <= colCount; j++)
{
//write the value to the console
if (rng.Cells[i, j] != null && rng.Cells[i, j].Value2 != null)
{
string tst = rng.Cells[i, j].Value2.ToString();
switch (j)
{
case 2:
companyName = tst;
break;
}
} //end of column
}//end of row
//write to database
string sql = "insert into dbo.company( ";
sql += DBI(companyName) + ")";
Console.WriteLine("sql = " + sql);
try
{
cmd.CommandText = sql;
cmd.ExecuteNonQuery();
}catch(Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
xlApp.Quit();
Marshal.ReleaseComObject(rng);
Marshal.ReleaseComObject(xlWorksheet);
Marshal.ReleaseComObject(xlWorkbook);
Marshal.ReleaseComObject(xlApp);
System.Threading.Thread.Sleep(3000);
}
and outside call looks like this:
ParseExcel(#"c:\testfile.xls", conn);
//cleanup
GC.Collect();
GC.WaitForPendingFinalizers();

I should not have made my parse method static. That was the cause of the memory leak.

Copying large datatable into excel in ASP.Net

I've written some code that copies the data from an Azure database into an Excel file. This can be found at the end of this question.
The problem is it takes forever to populate an excel sheet when I have 10k rows for one of the tables. Obviously, this is not ideal for Excel but at this point it has to be done this way. I'm wondering if there is a faster way to code this.
Certainly, creating excel sheet is the bottleneck, because C# grabs the dataset in seconds. If I go into Excel and view the data and then right click and copy with headers and paste that into and excel sheet it also does this in seconds.
So can I programmatically do this?
private void createExcelFile()
{
string fileName = "FvGReport.xlsx";
string filePath = HttpContext.Current.Request.MapPath("~/App_Data/" + fileName); //check www.dotnetperls.com/mappath
string sqlQuery = "";
List<string> sheetNames = new List<string>();
foreach (ListItem item in ddlSummary_Supplier.Items)
{
string sqlSummary = "SELECT * FROM FvGSummaryAll WHERE Supplier_Code = '" + item.Text + "'; ";
sqlQuery = sqlQuery + sqlSummary;
sheetNames.Add("Summary " + item.Text);
string sqlPaymentsSummary = "SELECT * FROM FvGSummaryPayment WHERE Supplier_Code = '" + item.Text + "'; ";
sqlQuery = sqlQuery + sqlPaymentsSummary;
sheetNames.Add("PaymentSummary " + item.Text);
}
DataSet dataSet = new DataSet();
//string sqlQuery = #"SELECT * FROM FvGData WHERE Supplier_Code = 'SFF Pacific'; SELECT * FROM FvGSummaryPayment";
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = new SqlCommand(sqlQuery, connection);
adapter.Fill(dataSet);
}
//this reference conflicts with System.Data as both have DataTable. So defining it here.
Microsoft.Office.Interop.Excel.Application ExcelApp = new Microsoft.Office.Interop.Excel.Application();
Microsoft.Office.Interop.Excel.Workbook excelWorkBook = null;
Microsoft.Office.Interop.Excel.Worksheet excelWorkSheet = null;
ExcelApp.Visible = true;
excelWorkBook = ExcelApp.Workbooks.Add(Microsoft.Office.Interop.Excel.XlWBATemplate.xlWBATWorksheet);
//excel rows start at 1 not 0
try
{
for (int i = 1; i < dataSet.Tables.Count; i++)
{
excelWorkBook.Worksheets.Add(); //Adds new sheet in Excel WorkBook
}
for (int i = 0; i < dataSet.Tables.Count; i++)
{
int dsRow = 1;
excelWorkSheet = excelWorkBook.Worksheets[i + 1];
//Writing Columns Name in Excel Sheet
for (int col = 1; col < dataSet.Tables[i].Columns.Count; col++)
{
excelWorkSheet.Cells[dsRow, col] = dataSet.Tables[i].Columns[col - 1].ColumnName;
}
dsRow++;
for (int xlRow = 0; xlRow < dataSet.Tables[i].Rows.Count; xlRow++)
{
//Excel row and col positions for writing row = 1, col = 1
for (int col = 1; col < dataSet.Tables[i].Columns.Count; col++)
{
excelWorkSheet.Cells[dsRow, col] = dataSet.Tables[i].Rows[xlRow][col - 1].ToString();
}
dsRow++;
}
excelWorkSheet.Name = sheetNames[i]; //Renaming ExcelSheets
}
excelWorkBook.SaveAs(filePath);
excelWorkBook.Close();
ExcelApp.Quit();
Marshal.ReleaseComObject(excelWorkSheet);
Marshal.ReleaseComObject(excelWorkBook);
Marshal.ReleaseComObject(ExcelApp);
}
catch (Exception ex)
{
lblNoData.Text = ex.ToString();
}
finally
{
foreach (Process process in Process.GetProcessesByName("Excel"))
{
process.Kill();
}
}
downloadExcel(filePath, fileName);
}

It looks like you're using Office Automation, which is usually slow on things like this, in my experience. I would suggest saving the output as a delimited file (.csv) and using automation to open that file (or files) with Excel and then save it as a spreadsheet.

I would suggest you to try using some ETL tool, Esspecially if you will do this from time to time again. If you take Talend, for instance, .... you connect to the DB and the schema will be pulled on its own. Take a SQL input component and connect it to a Excel component and you are done. Take about 5 minutes, without a single line of code

I'm not sure what you mean by 'forever', but for comparison I have a process that writes an OpenXML Spreadsheet of 46,124 row with ~500 characters per row in less than 17-seconds. This is generated on by a C# process that is on a separate server at the same hosting facility as the database server.
If writing to a CSV is an option, then that is going to be the solution with the best performance. OpenXML will give you the next best performance, I found the following article to be the most helpful when I was trying to put together my process:
Read-and-Write-Microsoft-Excel-with-Open-XML-SDK
Regarding memory -- You have two things you need to put in memory, your incoming data and your outgoing file. Regardless of what type of file you write, you'll want to use a SqlDataReader instead of your dataSet. This means your incoming data will only have one row at a time in memory (instead of all 10K). When writing your file (CSV or OpenXML) if you write directly to disk (FileStream) instead of memory (MemoryStream) you'll only have that little bit in memory.
Especially if you are running code that is running within your website, you don't want to use up a bunch of memory at once because .NET/IIS doesn't handle that very well.

Write data to Excel - C#

I need to write data to an excel sheet and need to open it after writing it. This is the code I am using..
object misValue = System.Reflection.Missing.Value;
Excel.Application xlAppEnv = new Excel.ApplicationClass();
Excel.Workbook xlForEnv = xlAppEnv.Workbooks.Add(misValue);
Excel.Worksheet xlForEnv_View = (Excel.Worksheet)xlForEnv.Worksheets.get_Item(1);
xlForEnv_View.Name = "PF Keys";
xlForEnv_View.Cells[row, column] = "data";
I could write data using the above code and when I am done, I could save the file to a predefined location using the below code..
envSaveLoc = envSaveLoc + "\\PF Keys.xlsx";
xlForEnv.SaveAs(envSaveLoc, Excel.XlFileFormat.xlOpenXMLWorkbook, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
xlAppEnv.DisplayAlerts = true;
xlForEnv.Close(true, misValue, misValue);
xlAppEnv.Quit();
The above code is working fine but now the requirement is that the program shouldn't save it but once the data is written to the excel sheet, open the file in excel and present to the user. User can then review and save it himself by using File->Save as option. How can I achieve it? The data can be stored in some temporary location for presenting to the user.

What about simply showing the Excel application window using
xlAppEnv.Visible = true;
This should display the Excel window with all the data you've written and let the user decide how to proceed.

This is what I use to run a SQL query and house the returned results in a data set then write the dataset to Excel. From there you can do whatever you wish with it, save/print/convertoPDF etc etc
int i = 0;
int j = 0;
_Workbook workbooksExcel;
Worksheet worksheet;
Excel._Application docExcel;
//This will run a SQL Query and write results to DataSet
SqlConnection conn;
string sql = null;
object misValue = System.Reflection.Missing.Value;
docExcel = null;
string ConnectionString = "Data Source=DS;Initial Catalog=TestDB;User ID = sa;Integrated Security=True;MultipleActiveResultSets=True";
conn = new System.Data.SqlClient.SqlConnection(ConnectionString);
conn.Open();
sql = "Insert SQL Statement Here";
System.Data.SqlClient.SqlDataAdapter dscmd = new System.Data.SqlClient.SqlDataAdapter(sql, conn);
ds = new DataSet();
dscmd.Fill(ds);
conn.Close();
//Here is where the above SQL Statement will write to Excel
for (i = 0; i <= SQLConnection.ds.Tables[0].Rows.Count - 1; i++)
{
for (j = 0; j <= SQLConnection.ds.Tables[0].Columns.Count - 1; j++)
{
try
{
data = ds.Tables[0].Rows[i].ItemArray[j].ToString();
_Workbook workbooksExcel = docExcel.ActiveWorkbook;
Worksheet sheetExcel = (Worksheet)workbooksExcel.ActiveSheet;
sheetExcel.Cells[i + 2, j + 1].Value = data;
}
catch (Exception ex) { }
}
}

Export Table from SQL Server to Excel 2007 using C#

my table in sql looks like this:
CREATE TABLE InjuryScenario
(
InjuryScenario_id int identity(1,1),
InjuryDay int,
InjuryMonth int,
InjuryYear int,
InjuryDesc varchar(80),
InjuryComments varchar(50),
AlmostInjury int,
InjuryInSchool varchar(20),
ProductInjury varchar(20),
Cause_id int,
CauseType_id int,
CauseChar_id int,
Place_id int,
PlaceType_id int,
InjuryDate_id int,
Username varchar(50),
TimeStamp datetime default (getdate()),
constraint pk_InjuryScenario_id primary key (InjuryScenario_id),
constraint fk_Cause_InjuryScenario foreign key(Cause_id) references Cause(Cause_id) on delete cascade,
constraint fk_CauseType_InjuryScenario foreign key(CauseType_id) references CauseType(CauseType_id) on delete no action,
constraint fk_CauseChar_InjuryScenario foreign key(CauseChar_id) references CauseChar(CauseChar_id) on delete no action,
constraint fk_Place_InjuryScenario foreign key(Place_id) references Place(Place_id) on delete cascade,
constraint fk_PlaceType_InjuryScenario foreign key(PlaceType_id) references PlaceType(PlaceType_id) on delete no action,
constraint fk_InjuryDate_InjuryScenario foreign key(InjuryDate_id) references InjuryDate(InjuryDate_id) on delete cascade,
constraint fk_Users_InjuryScenario foreign key(Username) references Users(Username) on delete cascade
)
I fill this table with data and i want to show this table in Excel 2007.
how can i do it using c#?
Thank you!

protected void insertBTN(object sender, EventArgs e)
{string conString = #"Data Source =XXXX; Initial Catalog=XXXX; Persist Security Info=True;User ID=XXXX; Password=XXXX";SqlConnection sqlCon = new SqlConnection(conString);
sqlCon.Open();
SqlDataAdapter da = new SqlDataAdapter("SELECT * from InjuryScenario", sqlCon);
System.Data.DataTable dtMainSQLData = new System.Data.DataTable();
da.Fill(dtMainSQLData);
DataColumnCollection dcCollection = dtMainSQLData.Columns;
// Export Data into EXCEL Sheet
Microsoft.Office.Interop.Excel.ApplicationClass ExcelApp = new
Microsoft.Office.Interop.Excel.ApplicationClass();
ExcelApp.Application.Workbooks.Add(Type.Missing);
// ExcelApp.Cells.CopyFromRecordset(objRS);
for (int i = 1; i < dtMainSQLData.Rows.Count + 2; i++)
{
for (int j = 1; j < dtMainSQLData.Columns.Count + 1; j++)
{
if (i == 1)
{
ExcelApp.Cells[i, j] = dcCollection[j - 1].ToString();
}
else
ExcelApp.Cells[i, j] = dtMainSQLData.Rows[i - 2][j - 1].ToString();
}
}
ExcelApp.ActiveWorkbook.SaveCopyAs("C:\\Users\\Mor Shivek\\Desktop\\test.xls");
ExcelApp.ActiveWorkbook.Saved = true;
ExcelApp.Quit();}

This is hundred percent working for VS-2013 Premium for C#. just copy
and paste the code That's it. Its working for SQL Server database You
can save the data into xls, xlsx, or csv and can use that same csv
for parameterization. you need to install following packages to make
it work.
using System.Data.SqlClient
using Excel=Microsoft.Office.Interop.Excel
using SQL = System.Data
///***Copy from here////
SqlConnection cnn;
string connectionstring = null;
string sql = null;
string data = null;
int i = 0;
int j = 0;
////*** Preparing excel Application
Excel.Application xlApp;
Excel.Workbook xlWorkBook;
Excel.Worksheet xlWorkSheet;
object misValue = System.Reflection.Missing.Value;
///*** Opening Excel application
xlApp = new Microsoft.Office.Interop.Excel.Application();
xlWorkBook = xlApp.Workbooks.Open(#"Fullpath\Book1.csv");
xlWorkSheet = (Excel.Worksheet)(xlWorkBook.ActiveSheet as Excel.Worksheet);
////*** It will always remove the prvious result from the CSV file so that we can get always the updated data
xlWorkSheet.UsedRange.Select();
xlWorkSheet.UsedRange.Delete(Excel.XlDeleteShiftDirection.xlShiftUp);
xlApp.DisplayAlerts = false;
//xlWorkBook.Save();
/////***Opening SQL Database using Windows Authentication
connectionstring = "Integrated Security = SSPI;Initial Catalog=DatabaseName; Data Source=ServerName;";
cnn = new SqlConnection(connectionstring);
cnn.Open();
////** Write your Sql Query here
sql = "SELECT TOP 10 [FirstName],[MiddleName],[LastName],[Email],[AltEmail],[AuthorizedUserName] From Tablename";
///*** Preparing to retrieve value from the database
SQL.DataTable dtable = new SQL.DataTable();
SqlDataAdapter dscmd = new SqlDataAdapter(sql, cnn);
SQL.DataSet ds = new SQL.DataSet();
dscmd.Fill(dtable);
////*** Generating the column Names here
string[] colNames = new string[dtable.Columns.Count];
int col = 0;
foreach (SQL.DataColumn dc in dtable.Columns)
colNames[col++] = dc.ColumnName;
char lastColumn = (char)(65 + dtable.Columns.Count - 1);
xlWorkSheet.get_Range("A1", lastColumn + "1").Value2 = colNames;
xlWorkSheet.get_Range("A1", lastColumn + "1").Font.Bold = true;
xlWorkSheet.get_Range("A1", lastColumn + "1").VerticalAlignment
= Excel.XlVAlign.xlVAlignCenter;
/////*** Inserting the Column and Values into Excel file
for (i = 0 ; i <= dtable.Rows.Count - 1; i++)
{
for (j = 0; j <= dtable.Columns.Count-1; j++)
{
data = dtable.Rows[i].ItemArray[j].ToString();
xlWorkSheet.Cells[i + 2, j + 1] = data;
}
}
///**Saving the csv file without notification.
xlApp.DisplayAlerts = false;
xlWorkBook.Save();
xlWorkBook.Close(true, misValue, misValue);
xlApp.Quit();
releaseObject(xlWorkSheet);
releaseObject(xlWorkBook);
releaseObject(xlApp);
}
private void releaseObject(object obj)
{
try
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
obj = null;
}
catch (Exception ex)
{
obj = null;
MessageBox.Show("Exception Occured while releasing object " + ex.ToString());
}
finally
{
GC.Collect();
}
}

I tried this code it's working.
private void button1_Click(object sender, EventArgs e)
{
SqlConnection cnn;
string connectionstring = null;
string sql = null;
string data = null;
int i = 0;
int j = 0;
Excel.Application xlApp;
Excel.Workbook xlWorkBook;
Excel.Worksheet xlWorkSheet;
object misValue = System.Reflection.Missing.Value;
xlApp = new Microsoft.Office.Interop.Excel.Application();
xlWorkBook = xlApp.Workbooks.Add(misValue);
xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
connectionstring ="Data Source=IN-WTS-SAM;Initial Catalog=MSNETDB;Integrated Security=True;Pooling=False";
cnn = new SqlConnection(connectionstring);
cnn.Open();
sql = "SELECT * FROM Emp";
SqlDataAdapter dscmd = new SqlDataAdapter(sql, cnn);
DataSet ds = new DataSet();
dscmd.Fill(ds);
for (i = 0; i <= ds.Tables[0].Rows.Count - 1; i++)
{
for (j = 0; j <= ds.Tables[0].Columns.Count - 1; j++)
{
data = ds.Tables[0].Rows[i].ItemArray[j].ToString();
xlWorkSheet.Cells[i + 1, j + 1] = data;
}
}
xlWorkBook.SaveAs("informations.xls", Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
xlWorkBook.Close(true, misValue, misValue);
xlApp.Quit();
releaseObject(xlWorkSheet);
releaseObject(xlWorkBook);
releaseObject(xlApp);
MessageBox.Show("Excel file created , you can find the file D:\\Sam-informations.xls");
}
private void releaseObject(object obj)
{
try
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
obj = null;
}
catch (Exception ex)
{
obj = null;
MessageBox.Show("Exception Occured while releasing object " + ex.ToString());
}
finally
{
GC.Collect();
}
}
}
Try this if it works for you.

Export sql table to excel with column name
for (i = 0; i <= ds.Tables[0].Columns.Count - 1; i++)
{
data = ds.Tables[0].Columns[i].ColumnName.ToString();
xlWorkSheet.Cells[1, i + 1] = data;
}

Import Excel file into Microsoft SQL Server using C#

I have a C# program that I want to import an Excel file into Microsoft SQL Server 2008 R2.
Can someone give me a link or tutorial where I can fully understand on how to this?
I've been doing this for a long time and I really don't have an idea on how to implement this.
Please help. Thanks.

string excelConnectionString = #"Provider=Microsoft
.Jet.OLEDB.4.0;Data Source=Book1.xls;Extended
Properties=""Excel 8.0;HDR=YES;""";
// Create Connection to Excel Workbook
We can Import excel to sql server like this
using (OleDbConnection connection =
new OleDbConnection(excelConnectionString)){
OleDbCommand command = new OleDbCommand
("Select ID,Data FROM [Data$]", connection);
connection.Open();
`// Create DbDataReader to Data Worksheet `
using (DbDataReader dr = command.ExecuteReader())
{
// SQL Server Connection String
string sqlConnectionString = "Data Source=.;
Initial Catalog=Test;Integrated Security=True";
// Bulk Copy to SQL Server
using (SqlBulkCopy bulkCopy =
new SqlBulkCopy(sqlConnectionString))
{
bulkCopy.DestinationTableName = "ExcelData";
bulkCopy.WriteToServer(dr);
}

This code may also help you.
private void processExcel(string filename)
{
filename = Server.MapPath("~/Files/WM-0b23-productsBook.xlsx");
Microsoft.Office.Interop.Excel.Application xlApp;
Microsoft.Office.Interop.Excel.Workbook xlWorkBook;
Microsoft.Office.Interop.Excel.Worksheet xlWorkSheet;
var missing = System.Reflection.Missing.Value;
xlApp = new Microsoft.Office.Interop.Excel.Application();
xlWorkBook = xlApp.Workbooks.Open(filename, false, true, missing, missing, missing, true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, '\t', false, false, 0, false, true, 0);
xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
Microsoft.Office.Interop.Excel.Range xlRange = xlWorkSheet.UsedRange;
Array myValues = (Array)xlRange.Cells.Value2;
int vertical = myValues.GetLength(0);
int horizontal = myValues.GetLength(1);
System.Data.DataTable dt = new System.Data.DataTable();
// must start with index = 1
// get header information
for (int i = 1; i <= horizontal; i++)
{
dt.Columns.Add(new DataColumn(myValues.GetValue(1, i).ToString()));
}
// Get the row information
for (int a = 2; a <= vertical; a++)
{
object[] poop = new object[horizontal];
for (int b = 1; b <= horizontal; b++)
{
poop[b - 1] = myValues.GetValue(a, b);
}
DataRow row = dt.NewRow();
row.ItemArray = poop;
dt.Rows.Add(row);
}
// assign table to default data grid view
GridView1.DataSource = dt;
GridView1.DataBind();
xlWorkBook.Close(true, missing, missing);
xlApp.Quit();
releaseObject(xlWorkSheet);
releaseObject(xlWorkBook);
releaseObject(xlApp);
}
private void releaseObject(object obj)
{
try
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
obj = null;
}
catch (Exception ex)
{
obj = null;
MessageBox.Show("Unable to release the Object " + ex.ToString());
}
finally
{
GC.Collect();
}
}

Check out this post :
Bulk Insertion of Data Using C# DataTable and SQL server OpenXML function
Import Data from Excel to SQL Server

I think that most useful answers already have been given.
I am not going to describe the C# way, but rathher give you an easy way of doing it without C#:
Open your MS Access, link your MS SQL database via ODBC, open your table in Access and paste your Excel records there via copy-paste (preformatted to match the table schema.)
This way is very fast and useful when you do some one-time data import.