c#计数器需要2个按钮点击才能更新
我有一个问题,一直在困扰着我整天。c#计数器需要2个按钮点击才能更新
在我的代码,我有以下:
private int rowCount
{
get { return (int)ViewState["rowCount"]; }
set { ViewState["rowCount"] = value; }
}
和按钮事件
protected void addRow_Click(object sender, EventArgs e)
{
rowCount = rowCount + 1;
}
然后在Page_Load中,我读了价值,并相应地创建控件。
我知道按钮事件触发后,Page_Load触发,所以值不会更新,直到下一个回发。真正的噩梦。
这里是整个代码:
protected void Page_Load(object sender, EventArgs e)
{
string xmlValue = ""; //To read a value from a database
if (xmlValue.Length > 0)
{
if (!Page.IsPostBack)
{
DataSet ds = XMLToDataSet(xmlValue);
Table dimensionsTable = DataSetToTable(ds);
tablePanel.Controls.Add(dimensionsTable);
DataTable dt = ds.Tables["Dimensions"];
rowCount = dt.Rows.Count;
colCount = dt.Columns.Count;
}
else
{
tablePanel.Controls.Add(DataSetToTable(DefaultDataSet(rowCount, colCount)));
}
}
else
{
if (!Page.IsPostBack)
{
rowCount = 2;
colCount = 4;
}
tablePanel.Controls.Add(DataSetToTable(DefaultDataSet(rowCount, colCount)));
}
}
protected void submit_Click(object sender, EventArgs e)
{
resultsLabel.Text = Server.HtmlEncode(DataSetToStringXML(TableToDataSet((Table)tablePanel.Controls[0])));
}
protected void addColumn_Click(object sender, EventArgs e)
{
colCount = colCount + 1;
}
protected void addRow_Click(object sender, EventArgs e)
{
rowCount = rowCount + 1;
}
public DataSet TableToDataSet(Table table)
{
DataSet ds = new DataSet();
DataTable dt = new DataTable("Dimensions");
ds.Tables.Add(dt);
//Add headers
for (int i = 0; i < table.Rows[0].Cells.Count; i++)
{
DataColumn col = new DataColumn();
TextBox headerTxtBox = (TextBox)table.Rows[0].Cells[i].Controls[0];
col.ColumnName = headerTxtBox.Text;
col.Caption = headerTxtBox.Text;
dt.Columns.Add(col);
}
for (int i = 0; i < table.Rows.Count; i++)
{
DataRow valueRow = dt.NewRow();
for (int x = 0; x < table.Rows[i].Cells.Count; x++)
{
TextBox valueTextBox = (TextBox)table.Rows[i].Cells[x].Controls[0];
valueRow[x] = valueTextBox.Text;
}
dt.Rows.Add(valueRow);
}
return ds;
}
public Table DataSetToTable(DataSet ds)
{
DataTable dt = ds.Tables["Dimensions"];
Table newTable = new Table();
//Add headers
TableRow headerRow = new TableRow();
for (int i = 0; i < dt.Columns.Count; i++)
{
TableCell headerCell = new TableCell();
TextBox headerTxtBox = new TextBox();
headerTxtBox.ID = "HeadersTxtBox" + i.ToString();
headerTxtBox.Font.Bold = true;
headerTxtBox.Text = dt.Columns[i].ColumnName;
headerCell.Controls.Add(headerTxtBox);
headerRow.Cells.Add(headerCell);
}
newTable.Rows.Add(headerRow);
//Add value rows
for (int i = 0; i < dt.Rows.Count; i++)
{
TableRow valueRow = new TableRow();
for (int x = 0; x < dt.Columns.Count; x++)
{
TableCell valueCell = new TableCell();
TextBox valueTxtBox = new TextBox();
valueTxtBox.ID = "ValueTxtBox" + i.ToString() + i + x + x.ToString();
valueTxtBox.Text = dt.Rows[i][x].ToString();
valueCell.Controls.Add(valueTxtBox);
valueRow.Cells.Add(valueCell);
}
newTable.Rows.Add(valueRow);
}
return newTable;
}
public DataSet DefaultDataSet(int rows, int cols)
{
DataSet ds = new DataSet();
DataTable dt = new DataTable("Dimensions");
ds.Tables.Add(dt);
DataColumn nameCol = new DataColumn();
nameCol.Caption = "Name";
nameCol.ColumnName = "Name";
nameCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(nameCol);
DataColumn widthCol = new DataColumn();
widthCol.Caption = "Width";
widthCol.ColumnName = "Width";
widthCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(widthCol);
if (cols > 2)
{
DataColumn heightCol = new DataColumn();
heightCol.Caption = "Height";
heightCol.ColumnName = "Height";
heightCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(heightCol);
}
if (cols > 3)
{
DataColumn depthCol = new DataColumn();
depthCol.Caption = "Depth";
depthCol.ColumnName = "Depth";
depthCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(depthCol);
}
if (cols > 4)
{
int newColCount = cols - 4;
for (int i = 0; i < newColCount; i++)
{
DataColumn newCol = new DataColumn();
newCol.Caption = "New " + i.ToString();
newCol.ColumnName = "New " + i.ToString();
newCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(newCol);
}
}
for (int i = 0; i < rows; i++)
{
DataRow newRow = dt.NewRow();
newRow["Name"] = "Name " + i.ToString();
newRow["Width"] = "Width " + i.ToString();
if (cols > 2)
{
newRow["Height"] = "Height " + i.ToString();
}
if (cols > 3)
{
newRow["Depth"] = "Depth " + i.ToString();
}
dt.Rows.Add(newRow);
}
return ds;
}
public DataSet XMLToDataSet(string xml)
{
StringReader sr = new StringReader(xml);
DataSet ds = new DataSet();
ds.ReadXml(sr);
return ds;
}
public string DataSetToStringXML(DataSet ds)
{
XmlDocument _XMLDoc = new XmlDocument();
_XMLDoc.LoadXml(ds.GetXml());
StringWriter sw = new StringWriter();
XmlTextWriter xw = new XmlTextWriter(sw);
XmlDocument xml = _XMLDoc;
xml.WriteTo(xw);
return sw.ToString();
}
private int rowCount
{
get { return (int)ViewState["rowCount"]; }
set { ViewState["rowCount"] = value; }
}
private int colCount
{
get { return (int)ViewState["colCount"]; }
set { ViewState["colCount"] = value; }
}
编辑:这是我的.aspx,以及如果你想尝试一下在VS.
<asp:Panel ID="tablePanel" runat="server" CssClass="table-panel" />
<asp:Label ID="resultsLabel" runat="server" />
<asp:LinkButton ID="submit" Text="submit" runat="server" onclick="submit_Click" />
<asp:LinkButton ID="addColumn" Text="Add Column" runat="server"
onclick="addColumn_Click" />
<asp:LinkButton ID="addRow" Text="Add Row" runat="server" onclick="addRow_Click" />
由于提前,
马尔科
好的我按照this后的说明解决了这个问题。
这是我的最终代码 - 如果您需要根据计数器创建动态控件,请随时使用它。
此外,我不介意对整体编码风格的反馈,我总是欣赏别人的意见。
protected void Page_Load(object sender, EventArgs e)
{
string xmlValue = ""; //To read a value from a database
if (xmlValue.Length > 0)
{
if (!Page.IsPostBack)
{
DataSet ds = XMLToDataSet(xmlValue);
Table dimensionsTable = DataSetToTable(ds);
tablePanel.Controls.Add(dimensionsTable);
DataTable dt = ds.Tables["Dimensions"];
rowCount = dt.Rows.Count;
colCount = dt.Columns.Count;
}
else
{
tablePanel.Controls.Add(DataSetToTable(DefaultDataSet(rowCount, colCount)));
}
}
else
{
if (!Page.IsPostBack)
{
rowCount = 2;
colCount = 4;
}
else
{
if (GetPostBackControl(this.Page).ID == "addRow")
{
rowCount = rowCount + 1;
}
else if (GetPostBackControl(this.Page).ID == "addColumn")
{
colCount = colCount + 1;
}
}
tablePanel.Controls.Add(DataSetToTable(DefaultDataSet(rowCount, colCount)));
}
}
protected void submit_Click(object sender, EventArgs e)
{
resultsLabel.Text = Server.HtmlEncode(DataSetToStringXML(TableToDataSet((Table)tablePanel.Controls[0])));
}
protected void addColumn_Click(object sender, EventArgs e)
{
}
protected void addRow_Click(object sender, EventArgs e)
{
}
public DataSet TableToDataSet(Table table)
{
DataSet ds = new DataSet();
DataTable dt = new DataTable("Dimensions");
ds.Tables.Add(dt);
//Add headers
for (int i = 0; i < table.Rows[0].Cells.Count; i++)
{
DataColumn col = new DataColumn();
TextBox headerTxtBox = (TextBox)table.Rows[0].Cells[i].Controls[0];
col.ColumnName = headerTxtBox.Text;
col.Caption = headerTxtBox.Text;
dt.Columns.Add(col);
}
for (int i = 0; i < table.Rows.Count; i++)
{
DataRow valueRow = dt.NewRow();
for (int x = 0; x < table.Rows[i].Cells.Count; x++)
{
TextBox valueTextBox = (TextBox)table.Rows[i].Cells[x].Controls[0];
valueRow[x] = valueTextBox.Text;
}
dt.Rows.Add(valueRow);
}
return ds;
}
public Table DataSetToTable(DataSet ds)
{
DataTable dt = ds.Tables["Dimensions"];
Table newTable = new Table();
//Add headers
TableRow headerRow = new TableRow();
for (int i = 0; i < dt.Columns.Count; i++)
{
TableCell headerCell = new TableCell();
TextBox headerTxtBox = new TextBox();
headerTxtBox.ID = "HeadersTxtBox" + i.ToString();
headerTxtBox.Font.Bold = true;
headerTxtBox.Text = dt.Columns[i].ColumnName;
headerCell.Controls.Add(headerTxtBox);
headerRow.Cells.Add(headerCell);
}
newTable.Rows.Add(headerRow);
//Add value rows
for (int i = 0; i < dt.Rows.Count; i++)
{
TableRow valueRow = new TableRow();
for (int x = 0; x < dt.Columns.Count; x++)
{
TableCell valueCell = new TableCell();
TextBox valueTxtBox = new TextBox();
valueTxtBox.ID = "ValueTxtBox" + i.ToString() + i + x + x.ToString();
valueTxtBox.Text = dt.Rows[i][x].ToString();
valueCell.Controls.Add(valueTxtBox);
valueRow.Cells.Add(valueCell);
}
newTable.Rows.Add(valueRow);
}
return newTable;
}
public DataSet DefaultDataSet(int rows, int cols)
{
DataSet ds = new DataSet();
DataTable dt = new DataTable("Dimensions");
ds.Tables.Add(dt);
DataColumn nameCol = new DataColumn();
nameCol.Caption = "Name";
nameCol.ColumnName = "Name";
nameCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(nameCol);
DataColumn widthCol = new DataColumn();
widthCol.Caption = "Width";
widthCol.ColumnName = "Width";
widthCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(widthCol);
if (cols > 2)
{
DataColumn heightCol = new DataColumn();
heightCol.Caption = "Height";
heightCol.ColumnName = "Height";
heightCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(heightCol);
}
if (cols > 3)
{
DataColumn depthCol = new DataColumn();
depthCol.Caption = "Depth";
depthCol.ColumnName = "Depth";
depthCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(depthCol);
}
if (cols > 4)
{
int newColCount = cols - 4;
for (int i = 0; i < newColCount; i++)
{
DataColumn newCol = new DataColumn();
newCol.Caption = "New " + i.ToString();
newCol.ColumnName = "New " + i.ToString();
newCol.DataType = System.Type.GetType("System.String");
dt.Columns.Add(newCol);
}
}
for (int i = 0; i < rows; i++)
{
DataRow newRow = dt.NewRow();
newRow["Name"] = "Name " + i.ToString();
newRow["Width"] = "Width " + i.ToString();
if (cols > 2)
{
newRow["Height"] = "Height " + i.ToString();
}
if (cols > 3)
{
newRow["Depth"] = "Depth " + i.ToString();
}
dt.Rows.Add(newRow);
}
return ds;
}
public DataSet XMLToDataSet(string xml)
{
StringReader sr = new StringReader(xml);
DataSet ds = new DataSet();
ds.ReadXml(sr);
return ds;
}
public string DataSetToStringXML(DataSet ds)
{
XmlDocument _XMLDoc = new XmlDocument();
_XMLDoc.LoadXml(ds.GetXml());
StringWriter sw = new StringWriter();
XmlTextWriter xw = new XmlTextWriter(sw);
XmlDocument xml = _XMLDoc;
xml.WriteTo(xw);
return sw.ToString();
}
private int rowCount
{
get { return (int)ViewState["rowCount"]; }
set { ViewState["rowCount"] = value; }
}
private int colCount
{
get { return (int)ViewState["colCount"]; }
set { ViewState["colCount"] = value; }
}
public static Control GetPostBackControl(Page page)
{
Control control = null;
string ctrlname = page.Request.Params.Get("__EVENTTARGET");
if (ctrlname != null && ctrlname != string.Empty)
{
control = page.FindControl(ctrlname);
}
else
{
foreach (string ctl in page.Request.Form)
{
Control c = page.FindControl(ctl);
if (c is System.Web.UI.WebControls.Button)
{
control = c;
break;
}
}
}
return control;
}
举动验证码:
tablePanel.Controls.Add(DataSetToTable(DefaultDataSet(rowCount, colC....
要预渲染事件使表绑定到其数据按钮点击后发射。
正如你所看到的,我在执行代码之前做了一系列检查。我已将整个代码块移至Page_PreRender事件,但tablePanel在submit_click上为空。 错误是: 指定的参数超出了有效值的范围。 resultsLabel.Text = Server.HtmlEncode(DataSetToStringXML(TableToDataSet((Table)tablePanel)。控制[0]))); – Marko 2010-05-10 05:42:29
任何想法为什么在PreRender中创建控件而不是Page_Load时提交的值不存在? – Marko 2010-05-10 05:53:01
正如我在this other question中推荐的那样,如果您希望在按钮“Click
”事件后执行一些页面逻辑,请将代码放入Page_PreRender
。
您可以在这里阅读更多关于它的信息:ASP.NET page life cycle。
编辑:
更加紧密地检查你的代码后,我看到你添加的东西,创造新的控制,这是不是在PreRender事件是一个好主意。 而是将代码放入单独的方法中。在Page_Load中,检查它是否是回传,如果不是,则处理该情况。 在按钮的单击evnt中,还要添加对该新方法的调用。 (因此处理IsPostback ==真实案例)
这GetPostBackControl是一个聪明的主意。 – Venemo 2010-05-11 08:19:46
注意:在这种情况下,这个实例等于this.Page实例。因此,你可以写“if(!IsPostBack)”或“GetPostBackControl(this)”。 (你的页面从页面类继承);) – Venemo 2010-05-11 08:21:31
是啊,感谢上帝,我发现它解决了我所有的问题!感谢您的帮助,我为您付出了努力+1。马尔科 – Marko 2010-05-11 20:48:15