In this post, i shared a few tips which i noted down during my first experience with WinForms.
1st Tip:
populating a combobox with enum :
this.comboBox.Items.AddRange(Enum.GetNames(typeof(MyEnumType)));
populating a combobox with collection:
List
sentenceList = server.retrieveSentences();
this.comboBoxSentences.DataSource =
sentenceList ;
this.comboBox
Sentences .DisplayMember = "SentenceCode";
this.comboBox
Sentences .ValueMember = "ID";
http://stackoverflow.com/questions/2417960/populating-a-combobox-using-c-sharp
2nd Tip:
the error message:
Unable to determine a valid ordering for dependent operations. Dependencies may exist due to foreign key constraints, model requirements, or store-generated values.
http://stackoverflow.com/questions/5532810/entity-framework-code-first-defining-relationships-keys
In my case, the problem was due to cascading deletions. Entity A includes a list of Entity B. And Entity S both includes Entity A and Entity B. In order to resolve it, i disabled cascade delete convention.
modelBuilder.Conventions.Remove
(<OneToManyCascadeDeleteConvention>);
3rd Tip:
several LINQ samples here:
http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b/viewsamplepack
4th Tip:
TreeView example:
// the selected sentence in the sentence tree
public Sentence selectedSentence;
// fills treeview with sentence list retrieved from database
private void fillTreeView()
{
// retrive sentences from database
List
sentenceList = server.retrieveSentences();
// this dictionary holds tree nodes. The key is the id of sentence.
Dictionary
treeNodeDict<int, TreeNode > = new Dictionary
(<int, TreeNode >);
// the root sentence of the tree
Sentence root = findRootNode(
sentenceList );
// root sentence is turned into a tree node.
TreeNode rootNode = this.treeView.Nodes.Add( root.Summary);
rootNode.Name = root.ID.ToString();
treeNodeDict.Add(root.ID, rootNode);
// main loop for constructing the treeview
foreach (var sentence in
sentenceList )
{
TreeNode parent;
// if dictionary contains the sentence, this means that sentence has been already
// converted to a tree node, so use it
if (treeNodeDict.ContainsKey(
sentence .ID))
{
parent = treeNodeDict[
sentence .ID];
}
// if dictionary does not contain the sentence, create a new tree node and
// add to dictionary for later reuse.
else
{
parent = new TreeNode(
sentence.Summar );
parent.Name =
sentence .ID.ToString();
treeNodeDict.Add(
sentence .ID, parent);
}
// the inner loop is to find the children of the parent node (the node in the main loop)
foreach (var child in
sentenceList)
{
// skip non-children nodes.
if (child.ParentSentenceID !=sentence.ID) continue;
TreeNode childNode;
if (treeNodeDict.ContainsKey(child.ID))
{
childNode = treeNodeDict[child.ID];
}
else
{
childNode = new TreeNode(child.Summary);
childNode.Name = child.ID.ToString();
treeNodeDict.Add(child.ID, childNode);
}
parent.Nodes.Add(childNode);
}
}
}
// finds root node of the list. root node is the node with no parent.
private Sentence findRootNode(List
sentenceList)
{
foreach (var sentence in
sentenceList )
{
if (sentence.ParentSentenceID == null || sentence.ParentSentenceID == 0) return sentence;
}
return null;
}
// the following methods are for turning the color of the selected node to green.
private void treeView_BeforeSelect(object sender, TreeViewCancelEventArgs e)
{
if (treeView.SelectedNode != null)
treeView.SelectedNode.ForeColor = Color.Black;
e.Node.ForeColor = Color.Green;
//
selected sentence in treeviw is highlighted to green
}
private void OwnerDrawAll(object sender, DrawTreeNodeEventArgs e)
{
if (((e.State & TreeNodeStates.Selected) != 0) && (!treeViewBirim.Focused))
e.Node.ForeColor = Color.Blue;
else
e.DrawDefault = true;
}
private void treeView_AfterSelect(object sender, TreeViewEventArgs e)
{
if (treeView.SelectedNode != null)
{
selectedSenetnce = server.retrieveSentenceByID(Int32.Parse(treeView.SelectedNode.Name));
treeView.Focus();
}
}
}
http://stackoverflow.com/questions/1838807/winforms-treeview-how-to-manually-highlight-node-like-it-was-clicked
http://www.java2s.com/Code/CSharp/GUI-Windows-Form/TreeViewExample.htm
http://www.java2s.com/Code/CSharp/GUI-Windows-Form/TreeViewDataBinding.htm
5th Tip:
Selected tabPage name:
http://stackoverflow.com/questions/3545624/return-selected-tabpage-name
tab.SelectedTab.Name
