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调用扩展方法(TreeNodeCollection Add方法)的正确方法是什么?

treenodecollection extension-methods winforms c#

0

VA systems engineer · 技术社区 · 7 年前

我的代码的相关部分如下。在 MyTreeView 类(下面最后一块代码),代码行 TncExtensions.TncNodeAdd(this, myTreeViewNode); 生成错误 CS7036 There is no argument given that corresponds to the required formal parameter 'myTreeViewNode' of 'TncExtensions.TncNodeAdd(TreeNodeCollection, MyTreeView_Abstract, MyTreeViewNode_Abstract)'

为什么编译器不知道TreeNodeCollection扩展方法的第二个形参是什么?

public static class TncExtensions
{
    public static int TncNodeAdd(this TreeNodeCollection nodes, MyTreeView_Abstract myTreeView, MyTreeViewNode_Abstract myTreeViewNode)
    {
        return myTreeView.Nodes.Add(myTreeViewNode);
    }
}

public abstract class MyTreeViewNode_Abstract : TreeNode
{
    public MyTreeViewNode_Abstract(string text) : base(text)
    {
    }
}

public class MyTreeViewNode : MyTreeViewNode_Abstract
{
    public MyTreeViewNode(string text) : base(text)
    {
    }
}

public abstract class MyTreeView_Abstract : TreeView
{
}

public class MyTreeView : MyTreeView_Abstract
{
    public void CreateTree()
    {
        MyTreeViewNode myTreeViewNode = new MyTreeViewNode("node text");
        TncExtensions.TncNodeAdd(this, myTreeViewNode);
    }
}

2 回复 | 直到 7 年前

1

blins 7 年前

TncExtensions.TncNodeAdd(Nodes, this, myTreeViewNode);

this.Nodes.TncNodeAdd(this, myTreeViewNode);

public static int TncNodeAdd(this TreeNodeCollection nodes, MyTreeViewNode_Abstract myTreeViewNode)
{
    return nodes.Add(myTreeViewNode);
}

2

1

VA systems engineer 7 年前

Add

修改了reza建议的添加扩展方法

namespace TreeNodeCollectionExtensions
{
    public static class TncExtensions
    {
        public static int Add(this TreeNodeCollection nodes, DRT.DRT_TvwNode_Abstract myTreeViewNode)
        {
            int newNodeIndex = nodes.Add(myTreeViewNode);

            //Do stuff to custom properties that are members of DRT_TvwNode_Abstract and classes derived from DRT_TvwNode_Abstract

            return newNodeIndex;
        }
    }
}

像这样用

using TreeNodeCollectionExtensions;

public class MyTreeView : MyTreeView_Abstract
{
    public MyTreeView() : base()
    {
    }

    public void CreateTree()
    {
        MyTreeViewNode myTreeViewNode;

        //Add node to root of TreeView 
        //Using named parameter to force the compiler to
        //use the Add extension method and not the base Add method
        myTreeViewNode = new MyTreeViewNode("root node text");
        Nodes.Add(myTreeViewNode: myTreeViewNode);

        //Add node one level below root node of TreeView
        //Using named parameter to force the compiler to
        //use the Add extension method and not the base Add method
        myTreeViewNode = new MyTreeViewNode("level 1 node text");
        int newLevel1NodeIndex = Nodes[0].Nodes.Add(myTreeViewNode: myTreeViewNode);

        //Add node one level below level 1 node just created 
        //Using named parameter to force the compiler to
        //use the Add extension method and not the base Add method
        myTreeViewNode = new MyTreeViewNode("level 2 node text");
        int newLevel2NodeIndex = Nodes[0].Nodes[newLevel1NodeIndex].Nodes.Add(myTreeViewNode: myTreeViewNode);

        //etc., etc.

    }
}