DateTime解析报错及DateTimePicker与DataGridView日期显示问题求助

1. Fixing the DateTime Parsing Error #

The error String '12/20/2022 12:00:00 AM' was not recognized as a valid DateTime occurs because your format string doesn’t match the input structure:

• Input string format: MM/dd/yyyy hh:mm:ss tt (month/day/year with 12-hour time)
• Your code uses dd-MM-YYYY (day-month-week-based year), which is completely mismatched.

Correct Approaches: #

• If the cell value is already a DateTime: Skip string conversion entirely (most reliable):

  DateTime dt = (DateTime)dgvSP.CurrentRow.Cells[5].Value;
  dtpQLSPnsx.Value = dt;
  

• If the cell value is stored as a string: Use the exact format matching your input:

  DateTime dt = DateTime.ParseExact(
      dgvSP.CurrentRow.Cells[5].Value.ToString(),
      "MM/dd/yyyy hh:mm:ss tt",
      CultureInfo.InvariantCulture
  );
  dtpQLSPnsx.Value = dt;
  

• For safer parsing: Use TryParseExact to avoid exceptions on invalid inputs:

  if (DateTime.TryParseExact(
      dgvSP.CurrentRow.Cells[5].Value.ToString(),
      "MM/dd/yyyy hh:mm:ss tt",
      CultureInfo.InvariantCulture,
      DateTimeStyles.None,
      out DateTime dt
  )) {
      dtpQLSPnsx.Value = dt;
  } else {
      // Handle invalid input here (e.g., show error message)
  }
  

2. Fixing DataGridView vs DateTimePicker Display Mismatch #

The DataGridView only showing the date part is controlled by its column’s formatting settings. Here’s how to align the displays:

Option A: Make DataGridView show full datetime (match DateTimePicker) #

Set the column’s DefaultCellStyle.Format to display the full datetime:

// Replace "DateColumnName" with your actual column name
dgvSP.Columns["DateColumnName"].DefaultCellStyle.Format = "MM/dd/yyyy hh:mm:ss tt";

Option B: Make DateTimePicker show only date (match DataGridView) #

If you prefer the DateTimePicker to display just the date, adjust its format properties:

// Use system default short date format
dtpQLSPnsx.Format = DateTimePickerFormat.Short;

// Or use a custom date format (e.g., MM/dd/yyyy)
dtpQLSPnsx.Format = DateTimePickerFormat.Custom;
dtpQLSPnsx.CustomFormat = "MM/dd/yyyy";

Note: Converting the DateTimePicker’s value to a date-only type won’t change how the DataGridView displays it—you need to adjust the grid’s column formatting directly.

内容的提问来源于stack exchange，提问作者Adudu123