c# - 保存视图状态和加载视图状态中的问题

Question

创建了自定义服务器控件

尝试将属性存储在视图状态但在回发时我无法获取先前存储在状态中的值。以下是代码

  private int attachmentId;
    public int AttachmentId
    {
        get { return attachmentId; }
        set { attachmentId = value; }
    }

  private string attachmentName = string.Empty;
    public string  AttachmentName
    {
        get { return attachmentName; }
        set { attachmentName = value; }
    }


 protected override void LoadViewState(object savedState)
    {
        object[] state = (object[])savedState;
        base.LoadViewState(state[0]);
        this.attachmentName = (string)state[1];
        this.attachmentId = (int)state[2];           
    }

 protected override void OnLoad(EventArgs e)
    {
        if(!IsPostBack)
        {
        this.AttachmentName ="HelloText.txt";
        this.AttachmentID = 10;
         }
    }

 protected override object SaveViewState()
    {
        object[] state = new object[3];
        state[0] = base.SaveViewState();
        state[1] = this.attachmentName;
        state[2] = this.attachmentId;

        return state;
    }

在第一页加载值被添加到视图状态如果任何回发将发生值应该是可用的，现在没有发生任何可以帮助我

Answer 1

您应该考虑以下选项来实现这一点。这是一种更简洁干净的实现方式。

类/枚举示例

public Color XXX
{
    get { return (Color)ViewState["XXX"]; }
    set { ViewState["XXX"] = value; }
}

布尔值示例

public bool AskForUpdate
{
        get
        {
            if (ViewState["AskForUpdate"] == null)
                return false;
            else
                return Convert.ToBoolean(ViewState["AskForUpdate"]);
        }
        set { ViewState["AskForUpdate"] = value; }
}

整数示例

 public int RevisionID
    {
        get
        {
            int revisionID = 0;
            int.TryParse(hdnRevisionID.Value, out revisionID);
            if (revisionID == 0)
            {
                if (Request.QueryString["ProposalID"] != null)
                {
                    if (int.TryParse(Request.QueryString["ProposalID"].ToString(), out revisionID))
                    {
                        hdnRevisionID.Value = revisionID.ToString();
                        return revisionID;
                    }
                }
            }
            else
            {
                return revisionID;
            }
            return revisionID;
        }
    }

字符串示例

 public string userGroup
    {
        get
        {
            if (ViewState["userGroup"] == null)
                return "";
            return (ViewState["userGroup"].ToString());
        }
        set { ViewState["userGroup"] = value; }
    }

在您现有的实现上也应该可以工作。您没有在 LoadViewState 中调用基本方法。

  base.LoadViewState(savedState);