Develop Reference

EPPLUS preserve date format when saving CSV

I am using EPPLUS to create a csv file. When I create an Excel file, I can format the date thus:
ws.Cells["A:A"].Style.Numberformat.Format = "yyyy-MMM-dd";
Which is what I need in my csv. However, if I try to save the worksheet as a csv, any dates end up as numbers.
***EDIT - I appreciate Excel stores the date as a serial number, I was just wondering if EPPLUS had a feature I can't locate to help me out.

Assuming you are setting the value to a proper DateTime value in code, you should be able to use the Text property of the cell like this:
var ws = package.Workbook.Worksheets.Add("Test");
ws.Cells["A:A"].Style.Numberformat.Format = "yyyy-MMM-dd";
ws.Cells["A1"].Value = DateTime.Now;
Console.WriteLine(ws.Cells["A1"].Text); // "2022-May-26"

Date format when importing from MySQL Date into the Textbox C#.NET

So I'm populating a DATE field in MySQL table from the DateTimePicker and on the other form I need to show the date in the textbox in "dd.MM.yyyy" format, but for some reason it populates the textbox in "MM/dd/yyyy HH:MM:SS" format.
I'm populating it simply like this:
tbDate.Text = dt.Rows[0][14].ToString();
How do i change the format?

Try following code
tbDate.Text = ((DateTime)dt.Rows[0][14]).ToString("dd.M.yyyy");

I need to show the date in the textbox in "dd.MM.yyyy" format
you need to first cast the value into DateTime type and then pass your Custom Date Format String to the ToString() function
Try This:
tbDate.Text = ((DateTime) dt.Rows[0][14]).ToString("dd.MM.yyyy");

Instead of changing the format in your C# code, directly fetch the date in the required format from database.
You can use the following query to fetch the date in dd.MM.yyyy format
select DATE_FORMAT(date_column,'%d.%m.%Y') FROM table_name;
Please refer this SQLFiddle Example
And then you can use your following code as it is,
tbDate.Text = dt.Rows[0][14].ToString();
Hope this helps :)

To Get Data that its type is Date in C#

In my SQL database, I have BeginDate column of type date (so I want to get only day,month,year).
I add data into database in C#.
I look at Table_Data and everything is fine (for example BeginDate = 05/04/2014).
But when I get this data from database in C# with
string a= dt.Rows[i]["BeginDate"].ToString()
result is: a= 05/04/2014 12:00:00 AM
Why?
I can remove hour in string a with any methods. But why? I want to get only 05/04/2014 from database.

This is a display problem, not a data problem. Use the Formatting features of DateTime.ToString() to display the date in the format that you want.
If the data is coming out of the database in string form, use DateTime.Parse on it first.
Reference
Standard Date and Time Formats
Custom Date and Time Formats

OleDb return Date Column value with time

I have Excel File(.xls) which contain date column without time value. I am trying to read this file and put it in datatable with connection string as below:
Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\Test\Desktop\1.xls; Extended Properties="Excel 8.0;HDR=YES;IMEX=1;ImportMixedTypes=Text"
Excel File Data
OleDb return datem value with time. 7/20/1995 12:00:00 AM
DataTable Data
But i want datem column value without time. Anyone have idea what i have to do to solve my problem.
Thanks.

.Net framework's DateTime consist of Date and Time. You can't really separate Time part from DateTime, instead you can use custom format for displaying records.
string str = DateTime.Today.ToString("MM/dd/yyyy");

I assume it's just a display issue in the DataSet visualizer. Actually it's a DateTime column which has no inherent format. So if you want to output a DateTime only with the date part:
string date = dt.ToShortDateString(); // or dt.ToString("d")
The Short Date ("d") Format Specifier

Problem with dates using CarlosAg.ExcelXmlWriter

I am using the CarlosAg.ExcelXmlWriter library to generate an Excel file in C#. If I treat all data as strings everything works fine, but I need some cells to be recognized by Excel as date fields. When I try to set the data type accordingly, the resulting Excel file fails to open in Excel 2003 (or Excel 2007 for that matter).
In Excel 2003, I get the following error on load:
Problems came up in the following area
during load: Table
I am using the following code to generate the DateTime cells that are causing the problem:
string val = DateTime.Now.ToString("MM/dd/yyyy");
row.Cells.Add(new WorksheetCell(val, DataType.DateTime));
Thanks.

I eventually figured this out. Thanks to Lance Roberts for nudging me in the right direction.
First, define a WorksheetStyle called dateStyle and set its NumberFormat property to a valid Excel date format:
Workbook book = new Workbook();
Worksheet sheet = book.Worksheets.Add("myWorksheet");
WorksheetStyle dateStyle = book.Styles.Add("dateStyle");
dateStyle.NumberFormat = "Dd Mmm Yy";
WorksheetRow row = book.Worksheets[0].Table.Rows.Add();
Then, export the date using the .NET "s" date format and add the cell:
string val = DateTime.Now.ToString("s");
row.Cells.Add(val, DataType.DateTime, "dateStyle");

I haven't used his library, but work in Excel a lot. I don't know what he's doing with a datatype for a cell, since they don't work that way. Dates in Excel cells are all integers with Date Formatting.
I would try to put the date in as an integer, the trick is converting your string to the correct integer. See this link for information on Excel's Date as Numbers methodology. I would then set the WorksheetStyle.NumberFormat Property.