C# 中的 Datagridview 没有从 SQL Server 数据库中检索所有记录

Question

I have a visual studio project for our student records and the records are coming from our online registration app. Then the database saves it. But the problem is my datagridview is not retrieving all the records from the database when I'm trying to retrive it using my other app. In other words our online app gathers data online and the other app is used to displays it for processing.

private void DisplayOnlineApplications(List<StudentInformationOnlineModel> Applicants)
{
    dataGridView1.Rows.Clear();

    foreach (var applicant in Applicants)
    {
        string gender = applicant.Gender.Substring(0, 1);
        dataGridView1.Rows.Add(applicant.ApplicationID, applicant.StudentStatus, applicant.LRN, applicant.StudentName, gender, applicant.EmailAddress, applicant.MobileNo, applicant.EducationLevel, applicant.CourseStrand, applicant.YearLevel, applicant.ApplicationDate.ToString("MM-dd-yyyy hh:mm tt"));
        dataGridView1.Rows[dataGridView1.Rows.Count - 1].Tag = applicant;
    }
}

Answer 1

Your code needs some improvements. You don't need to manually add rows. Simply do.

private void DisplayOnlineApplications(List<StudentInformationOnlineModel> Applicants)
{
    dataGridView1.DataSource = Applicants;
}

For Gender field you can handle DataGridView.CellFormatting event

private void DataGridView1_CellFormatting(
    object sender, DataGridViewCellFormattingEventArgs e)
{
    var dataPropertyName = dataGridView1.Columns[e.ColumnIndex].DataPropertyName;
    if (dataPropertyName == nameof(StudentInformationOnlineModel.Gender))
    {
        e.Value = (e.Value as string).Substring(0, 1);
    }
}

If you need to get your object in row then you can do (at index 0 for example)

var item = dataGridView1.Rows[0].DataBoundItem;
var studentInformationOnlineModel = item as StudentInformationOnlineModel;