Treenode填充空白節點C＃

我有一些代碼可以爲我的treeviews創建treenodes。一切工作正常的兩個foreach循環，但第三個'warnNode'不渲染節點文本 - 只是樹視圖的連接線。Treenode填充空白節點C＃

我已經通過了代碼，看到warnNode中的有效文本和子節點，我不知道爲什麼這不起作用。

 foreach (FundFamilySum ff in allCredits.FundFamilyCredits) 
     { 
      TreeNode fundFamilyNode = this.tvFundFamily.Nodes.Add(ff.FundFamilyName); 

      AddNodes(ff.BrokerCreditList, fundFamilyNode); 
      fundFamilyNode.ExpandAll(); 
     } 

     foreach (FundSum f in allCredits.FundCredits) 
     { 
      TreeNode fundNode = this.tvFund.Nodes.Add(f.FundName); 

      AddNodes(f.BrokerCreditList, fundNode); 
      fundNode.ExpandAll(); 
     } 

     TreeNode warnNode = this.tvWarnings.Nodes.Add("Warnings"); 
     foreach (WarningCredit w in allCredits.WarningCredits) 
     { 
      warnNode.Nodes.Add(string.Format("{0} with {1} - {2} Utilization", w.FundOrFamName, w.Credit.BrokerName, String.Format("{0:0%}", w.Credit.UtilPct))); 
      //TreeNode warnChildNode = warnNode.Nodes.Add(w.Credit.BrokerName + " - " + String.Format("{0:0%}", w.Credit.UtilPct) + " Utilization") 

     } 
     warnNode.ExpandAll();

這裏是被渲染，它好像有那麼點意思，如藍色高亮部分是爲我的文字正確的尺寸，但文字本身不顯示。
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