[英]User Defined controls on web form
使用VS 2010,C#、. NET 3.5
我有三個用戶定義的Web控件:
控件1有一個列表框和一個按鈕
控件2具有三個Text-Boxes
兩個DropDownLists
和三個Buttons
控件3僅具有一個用代碼填充的表。
我有兩個頁面:
頁面1具有控件2和控件3
頁面2具有控件1,控件2和控件3
控制2的功能在第1頁上完美工作。
但是,在第2頁上,單擊“提交”按鈕時,兩個DropDownLists都始終顯示SelectedIndex = 0
和SelectedValue = "0"
。
單擊控件2上的Submit Button時,所有三個文本框和按鈕在兩個頁面上均保留其值。 僅DropDownLists無法保留其值。
供參考,這是Submit Button OnClick事件中的代碼:
protected void btnSubmit_Click(object sender, EventArgs e)
{
clsLog.WriteLog("TrainingForm.ascx - Submit.");
tcCategoryError.Text = " ";
tcDateError.Text = " ";
tcDescriptionError.Text = " ";
tcHoursError.Text = " ";
tcMethodError.Text = " ";
foreach (Control c in this.Controls)
{
LogControls(c);
}
c_iTID = Convert.ToInt32(hTID.Value);
c_szUserName = hUserName.Value;
bool bValid = true;
DateTime dtTrainingDate = DateTime.MinValue;
string szTrainingDescription = "";
decimal dHours = 0M;
int iCategoryID = 0;
int iMethodID = 0;
if (!DateTime.TryParse(txtTrainingDate.Text, out dtTrainingDate))
{
bValid = false;
tcDateError.Text = "Please Enter Valid Training Date";
}
if (!decimal.TryParse(txtTrainingHours.Text, out dHours))
{
bValid = false;
tcHoursError.Text = "Please Enter Valid Training Hours";
}
if (this.ddlCategory.SelectedValue == "0")
{
bValid = false;
tcCategoryError.Text = "Please Select Training Category";
}
else
iCategoryID = Convert.ToInt32(this.ddlCategory.SelectedValue);
if (this.ddlTrainingMethod.SelectedValue == "0")
{
bValid = false;
tcMethodError.Text = "Please Select Training Method";
}
else
iMethodID = Convert.ToInt32(this.ddlTrainingMethod.SelectedValue);
if (txtTrainingDescription.Text.Trim() == "")
{
bValid = false;
tcDescriptionError.Text = "Please Enter Training description.";
}
else
szTrainingDescription = txtTrainingDescription.Text.Trim();
if (bValid)
{
clsData.UpdateTraining(c_iTID, "", c_szUserName, dtTrainingDate, szTrainingDescription, iCategoryID, dHours, iMethodID);
TrainingID = 0;
ClearForm();
}
OnEvent(new MyEventArgs(c_szUserName));
}
填充DropDowns的代碼(用戶定義控件的一部分)
protected void BindddlCategory(int iCategoryID)
{
DataTable dt = clsData.GetTrainingCategories();
ddlCategory.Items.Clear();
ddlCategory.AppendDataBoundItems = true;
ddlCategory.Items.Add(new ListItem("Select Training Category", "0"));
ddlCategory.DataSource = dt;
ddlCategory.DataTextField = "TrainingCategory";
ddlCategory.DataValueField = "CID";
ddlCategory.DataBind();
if (iCategoryID != 0)
ddlCategory.SelectedValue = iCategoryID.ToString();
}
protected void BindddlCategory()
{
BindddlCategory(0);
}
protected void BindddlTrainingMethod(int iMethodID)
{
DataTable dt = clsData.GetTrainingMethods();
ddlTrainingMethod.Items.Clear();
ddlTrainingMethod.AppendDataBoundItems = true;
ddlTrainingMethod.Items.Add(new ListItem("Select Training Method", "0"));
ddlTrainingMethod.DataSource = dt;
ddlTrainingMethod.DataTextField = "TrainingCategory";
ddlTrainingMethod.DataValueField = "CID";
ddlTrainingMethod.DataBind();
if (iMethodID != 0)
ddlTrainingMethod.SelectedValue = iMethodID.ToString();
}
protected void BindddlTrainingMethod()
{
BindddlTrainingMethod(0);
}
僅供參考,在頁面加載時不會填充DDL,而是在觸發顯示控件形式的事件時隱式填充DDL:
public void ShowTrainingEntry(int iTrainingID)
{
clsLog.WriteLog("TrainingForm.ascx - ShowTrainingEntry(" + iTrainingID.ToString() + ")");
hTID.Value = iTrainingID.ToString();
hUserName.Value = UserName;
int iCategoryID = 0;
int iMethodID = 0;
if (iTrainingID != 0)
{
DataTable dt = clsData.GetTrainingRecord(iTrainingID);
if (dt.Rows.Count == 1)
{
txtTrainingDate.Text = Convert.ToDateTime(dt.Rows[0]["TrainingDate"]).ToString("MM/dd/yyyy");
txtTrainingHours.Text = Convert.ToDecimal(dt.Rows[0]["Hours"]).ToString("N1");
txtTrainingDescription.Text = dt.Rows[0]["TrainingDescription"].ToString();
int.TryParse(dt.Rows[0]["CategoryCID"].ToString(), out iCategoryID);
int.TryParse(dt.Rows[0]["MethodCID"].ToString(), out iMethodID);
}
ShowChangeMessage(iCategoryID == 0 | iMethodID == 0);
ShowDeleteButton(true);
ShowCancelButton(true);
}
BindddlCategory(iCategoryID);
BindddlTrainingMethod(iMethodID);
tblMain.Visible = true;
}
有人對為什么會這樣有任何想法嗎?
謝謝,約翰
如果要動態添加UserControl,則需要確保不遲於Page_Init添加它們。 這樣,當頁面嘗試從PostBack設置值時,控件就出現了。
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