Finding Start and End Dates of Previous Week

private void GetDates(ref System.DateTime stDate, ref System.DateTime endDate)
{
double offset = 0;
switch (System.DateTime.Today.DayOfWeek)
{
case DayOfWeek.Monday:
offset = 0;
break;
case DayOfWeek.Tuesday:
offset = -1;
break;
case DayOfWeek.Wednesday:
offset = -2;
break;
case DayOfWeek.Thursday:
offset = -3;
break;
case DayOfWeek.Friday:
offset = -4;
break;
case DayOfWeek.Saturday:
offset = -5;
break;
case DayOfWeek.Sunday:
offset = -6;
break;
}
endDate = System.DateTime.Today.AddDays(offset);
stDate = System.DateTime.Today.AddDays(-7 + offset);
}
courtesy : http://www.knowdotnet.com/articles/getpreviousmonday.html

Import from excel to datatable

private void btnImport_Click(object sender, EventArgs e)
{
OpenFileDialog openfileDialog1 = new OpenFileDialog();
openfileDialog1.Filter = "Excel files only (*.xls)|";
if (openfileDialog1.ShowDialog() == DialogResult.OK)
{
string FNExtn = Path.GetFileName(openfileDialog1.FileName);

string FN = Path.GetExtension(openfileDialog1.FileName);
string SaveLocation = Path.GetFullPath(openfileDialog1.FileName);
if (FN == ".xls")
{
sExcelConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" + SaveLocation + "; Extended Properties=\"Excel 8.0;IMEX=1;\"";
Import_sample(FNExtn);

}
else if (FN == ".xlsx")
{
sExcelConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + SaveLocation + ";Extended Properties=\"Excel 12.0;HDR=YES;\"";

Import_sample(FNExtn);

}
else if (FN != "xls" || FN != "xlsx")
{

//Alert message "Please Select an Excel File to import!"
}

}
}



private void Import_sample(string FNE)
{
DataSet myDataSet = new DataSet();
DataTable dtFile = new DataTable();
try
{
//You must use the $ after the object you reference in the spreadsheet
OleDbConnection excelConnection = new OleDbConnection(sExcelConnectionString);
excelConnection.Open();

DataTable dtSheetName = new DataTable();

dtSheetName = excelConnection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
string SheetName = "";
foreach (DataRow row in dtSheetName.Rows)
{
string strSheetTableName = row["TABLE_NAME"].ToString(); //dtSheetName.Rows[0]["TABLE_NAME"].ToString();
if (strSheetTableName.Length > 1)
SheetName = strSheetTableName.Substring(0, strSheetTableName.Length - 1).Replace("$", "").Replace("'", "");

OleDbDataAdapter myCommand = new OleDbDataAdapter("SELECT * FROM [" + SheetName + "$]", sExcelConnectionString);
myCommand.Fill(myDataSet, "Import");

if (myDataSet.Tables["Import"].Rows.Count > 0 && SheetName == "Sheet1")
{

dtFile = myDataSet.Tables["Import"]; // All the records are filled in a datatable - dtFile

string sheet1col1 = dtFile.Columns[0].ColumnName.ToString().Trim().Replace(":", "");
string sheet1col2 = dtFile.Columns[1].ColumnName.ToString().Trim().Replace(":", "");

if (sheet1col1.Trim() == "Name" && sheet1col2.Trim() == "Type") // (SheetName == sheet)
{


}


}
}
}
catch (Exception)
{
throw;
}
}

Custom Active Directory user authentication

This function helps to authenticate user in active directory. Can use provide windows authentication in a form authentication websites too.

DNS Name format: "LDAP://DNSName"

private bool ValidateUser(string dnsname,string username,string password)
{
try
{
DirectoryEntry entry = new DirectoryEntry(dnsname, username, password);
DirectorySearcher mySearcher = new DirectorySearcher(entry);
SearchResultCollection results;
mySearcher.Filter = "cn";
results = mySearcher.FindAll();
if (results == null)
{
lblError.Text = "Invalid User";
return false;
}
else
{
lblError.Text = "User Found";
return true;
}
}
catch
{
lblError.Text = "Invalid User";
return false;
}
}

File Size Formatting in C#

Have you ever wanted to display the size of the file in bytes, kilo bytes or mega bytes, here is a simple code snippet to do that.


private string FormatSize (double fileSize)
{
if (fileSize < 1024)
return String.Format(”{0:N0} B”, fileSize);
else if (fileSize < 1024*1024)
return String.Format(”{0:N2} KB”, fileSize/1024);
else
return String.Format(”{0:N2} MB”, fileSize/(1024*1024));
}


[Posted By Yenkay]