在TreeView中添加父节点和子节点

Question

我想从SQL server添加父节点和子节点到treeview。我实现了一些代码。但是它得到错误"Index was out of range"

下面是我用来填充父节点和子节点的代码。

protected void GetParentNodes()
    {
        SqlDataAdapter adap = new SqlDataAdapter("select id, name from crossarticle_category where parentid=-1", con);
        DataTable dt = new DataTable();
        adap.Fill(dt);
        int index = -1;
        foreach (DataRow d in dt.Rows)
        {
            SqlDataAdapter adapInner = new SqlDataAdapter("select id, name from crossarticle_category where parentid=" + Convert.ToInt32(d["id"].ToString()) + "", con);
            DataTable dtInner = new DataTable();
            adapInner.Fill(dtInner);
            index++;
            TreeNode n = new TreeNode();
            n.Value = d["id"].ToString();
            n.Text = d["name"].ToString();
            foreach (DataRow r in dtInner.Rows)
            {
                if (dtInner.Rows.Count > 0)
                {
                    TreeNode inner = new TreeNode();
                    inner.Value = r["id"].ToString();
                    inner.Text = r["name"].ToString();
                    tree1.Nodes[index].ChildNodes.Add(inner);
                }
            }
            tree1.Nodes.Add(n);
        }
    }

谁能帮我纠正这段代码中的问题…这段代码是我自己写的

Answer 1

看起来您试图在添加父节点之前添加子节点。尝试先添加父节点，然后添加子节点;像这样:

///...
n.Value = d["id"].ToString();
n.Text = d["name"].ToString();
tree1.Nodes.Add(n);

然后

foreach (DataRow r in dtInner.Rows)
{
    if (dtInner.Rows.Count > 0)
    {
        TreeNode inner = new TreeNode();
        inner.Value = r["id"].ToString();
        inner.Text = r["name"].ToString();
        tree1.Nodes[index].ChildNodes.Add(inner); //node at pos index should exist now
     }
}