如何在子节点树视图中添加复选框? [英] How to add checkbox in childnodes treeview?

问题描述

我正在使用 c# 在 .NET 3.5 中使用 winforms.现在我想在子节点中添加带有父节点和复选框的树视图...

I am working with winforms in .NET 3.5 using c#. now i want to add treeview with parent nodes and checkboxes in child nodes...

我已经通过以下代码完成了父节点的创建..

I have completed parent node creation by following code..

dt = conn.dataTable("select desgn from designation");
tvRoles.Nodes.Clear();
foreach (DataRow dr in dt.Rows)
{
     TreeNode parent = new TreeNode();
     parent.Text = dr[0].ToString();
     string value = dr[0].ToString();
     parent.Expand();
     tvRoles.Nodes.Add(parent);
     subLevel(parent, value);
}

现在我想在子节点中添加复选框..

Now I want to add checkboxes in child nodes..

你能帮助我吗?

推荐答案

如果你希望只有子节点有复选框，这里有一个解决方案:

If you want only children nodes have checkboxes, here is a solution:

//First, as I said, you have to set treeView.CheckBoxes = true;
//Second, set treeView.DrawMode = TreeViewDrawMode.OwnerDrawAll;
//Add this DrawNode event handler and enjoy =)
private void treeView_DrawNode(object sender, DrawTreeNodeEventArgs e)
{
    if (e.Node.Parent == null)//If the Node is a Parent
    {                
        int d = (int)(0.2*e.Bounds.Height);
        Rectangle rect = new Rectangle(d + treeView.Margin.Left, d + e.Bounds.Top, e.Bounds.Height - d*2, e.Bounds.Height - d*2);
        e.Graphics.FillRectangle(new SolidBrush(Color.FromKnownColor(KnownColor.Control)), rect);
        e.Graphics.DrawRectangle(Pens.Silver, rect);
        StringFormat sf = new StringFormat() { LineAlignment = StringAlignment.Center, Alignment = StringAlignment.Center };
        e.Graphics.DrawString(e.Node.IsExpanded ? "-" : "+", treeView.Font, new SolidBrush(Color.Blue), rect, sf); 
        //Draw the dotted line connecting the expanding/collapsing button and the node Text
        using (Pen dotted = new Pen(Color.Black) {DashStyle = System.Drawing.Drawing2D.DashStyle.Dot})
        {
          e.Graphics.DrawLine(dotted, new Point(rect.Right + 1, rect.Top + rect.Height / 2), new Point(rect.Right + 4, rect.Top + rect.Height / 2));
        }               
        //Draw text
        sf.Alignment = StringAlignment.Near;
        Rectangle textRect = new Rectangle(e.Bounds.Left + rect.Right + 4, e.Bounds.Top, e.Bounds.Width - rect.Right - 4, e.Bounds.Height);
        if (e.Node.IsSelected)
        {
            SizeF textSize = e.Graphics.MeasureString(e.Node.Text, treeView.Font);
            e.Graphics.FillRectangle(new SolidBrush(SystemColors.Highlight), new RectangleF(textRect.Left, textRect.Top, textSize.Width, textRect.Height));
        }
        e.Graphics.DrawString(e.Node.Text, treeView.Font, new SolidBrush(treeView.ForeColor), textRect,sf);
    }
    else e.DrawDefault = true;
}

为了使它更好，您可能想要创建自己的 TreeView，覆盖 OnDrawNode(使用与我上面发布的相同的代码)并设置 DoubleBuffered=在构造函数中为 true.

To make it better, you may want to create your own TreeView, override OnDrawNode (with the same code as I posted above) and set DoubleBuffered=true in the constructor.

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