Introduction
This is the first of the three posts on this topic. The Paint
event is called when DataGridView
needs repainting on account of changes to the grid. One of the requirements of
a project was to display a No records
available message when there are no records. Rather than having checking record count each time records are fetched from database, its better to check condition only when grid is drawn. In this post I will explain
how to use the Paint event to do
this.
The following example illustrates how to use this event to
customize the grid.
1.
Open Visual Studio and create a new Windows
Forms project.
2.
Rename Form1 to Dashboard.
3.
Open Dashboard
form in Designer mode.
4.
From Toolbox drag the following to the form:
a.
DataGridView control
b.
labelForEmptyRows .
5.
Click the arrow on DataGridView to define column
header and column types.
6.
In the Add
columns window, set the column name, type(button column, text column etc.) and
header text
7.
The final layout would be as seen in the
following screenshot
8.
To populate the grid with some data, add the
following code to the form.
public Dashboard()
{
InitializeComponent();
IList<CourseEntity>
CourseList = PopulateGrid();
foreach(CourseEntity
courseEntity in CourseList)
dgvDashboard.Rows.Add(courseEntity.Id, courseEntity.CourseName,courseEntity.Status);
}
public IList<CourseEntity>
PopulateGrid()
{
List<CourseEntity>
courseList = new List<CourseEntity>();
courseList.Add(new CourseEntity { Id = "1", CourseName = "Asp.NET
MVC3", Status = "Available" });courseList.Add(new CourseEntity { Id = "2", CourseName = "Asp.NET MVC4", Status = "Available" });
courseList.Add(new CourseEntity { Id = "3", CourseName = "C#", Status = "Available" });
courseList.Add(new CourseEntity { Id = "4", CourseName = "Metro
Apps", Status = "Available" });
//return courseList.Cast<CourseEntity>().ToList();
return courseList;
}public class CourseEntity
{
public string Id { get; set; }
public string CourseName { get; set; }
public string Status { get; set; }
}
9.
The expected output will be like this.
11. For providing text on buttons in Borrow Column. Go to edit columns in datagridview.
Set the properties as shown.
12.
For removing this extra row at bottom, set
“AllowUserToAddRows” property of datagridview to false.
13.
Now, comment out the code in Dashboard() so that
no records are populated to grid.
public Dashboard()
{
InitializeComponent();
//IList<CourseEntity> CourseList = PopulateGrid();
//foreach(CourseEntity courseEntity in CourseList)
//
dgvDashboard.Rows.Add(courseEntity.Id, courseEntity.CourseName,
courseEntity.Status);
}
14.
In the paint event of DataGridView add the
following code.
private void dgvDashboard_Paint(object sender, PaintEventArgs e) {
if (dgvDashboard.Rows.Count
== 0)
lblEmptyRows.Visible = true;
else
lblEmptyRows.Visible = false;
}
15.
See the output now.
Conclusion
We learnt how we can leverage the Paint event of DataGridView,
how to design a DataGridView view with different column types and
AllowUserToAddRows Property.
In next part I will cover how to make images as buttons in DataGridView
and define click events for them. Stay tuned J
