Using Client Callbacks for Building the ListBoxesFTs_C ASP.NET Web User Control: Part II

{

get { return _DT_Out; }

}

#endregion

private DataTable dataTable_Sort(DataTable dt)

{

DataView dv;

DataTable dtHelp;

DataRow dr;

int iCount = 0;

int iMax = dt.Rows.Count;

dtHelp = dt.Copy();

dv = dtHelp.DefaultView;

dv.Sort = dt.Columns[_SortBy].Caption;

dt.Clear();

for (iCount = 0; iCount < iMax; iCount++)

{

dr = dt.NewRow();

dr[0] = dv[iCount][0];

dr[1] = dv[iCount][1];

dt.Rows.Add(dr);

}

return dt;

}

//-----------------------------------------------------

private void fillHidden(DataTable dt,

HtmlInputHidden HiddenText,

HtmlInputHidden HiddenValue)

{

int iCount;

int iMax;

string sHiddenText = "";

string sHiddenValue = "";

string sText = "";

string sValue = "";

iMax = dt.Rows.Count;

for (iCount = 0; iCount < iMax; iCount++)

{

sText = dt.Rows[iCount][1].ToString().Trim();

sValue = dt.Rows[iCount][0].ToString().Trim();

sHiddenText += sText;

sHiddenValue += sValue;

if (iCount != (iMax - 1))

{

sHiddenText += _Split;

sHiddenValue += _Split;

}

}

HiddenText.Value = sHiddenText;

HiddenValue.Value = sHiddenValue;

}

//-----------------------------------------------------

private void buildListBox(ListBox lb, DataTable dt)

{

lb.DataTextField = dt.Columns[1].Caption;

lb.DataValueField = dt.Columns[0].Caption;

lb.DataSource = dt;

lb.DataBind();

}

//-----------------------------------------------------

private void getDT_Hidden()

{

Array arrFromText;

Array arrFromValue;

Array arrToText;

Array arrToValue;

char[] separator ={ (char)_Split[0] };

DataRow dr;

int iCount;

int iMax;

arrFromText = HiddenFromText.Value.ToString().Trim().Split(separator);

arrFromValue = HiddenFromValue.Value.ToString().Trim().Split(separator);

iMax = arrFromText.Length;

_DT_In.Clear();

for (iCount = 0; iCount < iMax; iCount++)

{

dr = _DT_In.NewRow();

dr[0] = arrFromValue.GetValue(iCount);

dr[1] = arrFromText.GetValue(iCount);

if (arrFromValue.GetValue(iCount).ToString().Trim() != ""

&& arrFromText.GetValue(iCount).ToString().Trim() != "")

{

_DT_In.Rows.Add(dr);

}

}

arrToText = HiddenToText.Value.ToString().Trim().Split(separator);

arrToValue = HiddenToValue.Value.ToString().Trim().Split(separator);

iMax = arrToText.Length;

_DT_Out.Clear();

for (iCount = 0; iCount < iMax; iCount++)

{

dr = _DT_Out.NewRow();

dr[0] = arrToValue.GetValue(iCount);

dr[1] = arrToText.GetValue(iCount);

if (arrToValue.GetValue(iCount).ToString().Trim() != ""

&& arrToText.GetValue(iCount).ToString().Trim() != "")

{

_DT_Out.Rows.Add(dr);

}

}

}

private void getDT_Hidden(

string textHiddenFromText,

string textHiddenFromValue,

string textHiddenToText,

string textHiddenToValue)

{

Array arrFromText;

Array arrFromValue;

Array arrToText;

Array arrToValue;

char[] separator ={ (char)_Split[0] };

DataRow dr;

int iCount;

int iMax;

arrFromText = textHiddenFromText.Split(separator);

arrFromValue = textHiddenFromValue.Split(separator);

iMax = arrFromText.Length;

_DT_In.Clear();

for (iCount = 0; iCount < iMax; iCount++)

{

dr = _DT_In.NewRow();

dr[0] = arrFromValue.GetValue(iCount);

dr[1] = arrFromText.GetValue(iCount);

if (arrFromValue.GetValue(iCount).ToString().Trim() != ""

&& arrFromText.GetValue(iCount).ToString().Trim() != "")

{

_DT_In.Rows.Add(dr);

}

}

arrToText = textHiddenToText.Split(separator);

arrToValue = textHiddenToValue.Split(separator);

iMax = arrToText.Length;

_DT_Out.Clear();

for (iCount = 0; iCount < iMax; iCount++)

{

dr = _DT_Out.NewRow();

dr[0] = arrToValue.GetValue(iCount);

dr[1] = arrToText.GetValue(iCount);

if (arrToValue.GetValue(iCount).ToString().Trim() != ""

&& arrToText.GetValue(iCount).ToString().Trim() != "")

{

_DT_Out.Rows.Add(dr);

}

}

}

//-----------------------------------------------------

protected override void LoadViewState(object VS_saved)

{

if (VS_saved != null)

{

object[] VS_all = (object[])VS_saved;

if (VS_all[0] != null)

{

base.LoadViewState(VS_all[0]);

}

if (VS_all[1] != null)

{

_DT_In = (DataTable)VS_all[1];

}

if (VS_all[2] != null)

{

_DT_Out = (DataTable)VS_all[2];

}

if (VS_all[3] != null)

{

_SortBy = (int)VS_all[3];

}

if (VS_all[4] != null)

{

_WidthLB = (int)VS_all[4];

}

if (VS_all[5] != null)

{

_HeightLB = (int)VS_all[5];

}

if (VS_all[6] != null)

{

_LabelFrom = (string)VS_all[6];

}

if (VS_all[7] != null)

{

_LabelTo = (string)VS_all[7];

}

}

}

protected override object SaveViewState()

{

object VS_base = base.SaveViewState();

object[] VS_all = new object[8];

VS_all[0] = VS_base;

VS_all[1] = _DT_In;

VS_all[2] = _DT_Out;

VS_all[3] = _SortBy;

VS_all[4] = _WidthLB;

VS_all[5] = _HeightLB;

VS_all[6] = _LabelFrom;

VS_all[7] = _LabelTo;

return VS_all;

}

}

The full client script of the ListBoxesFTs_C.ascx:

<script language="javascript" type="text/javascript">

// <!CDATA[

//--------------------------------------

var _Split = "|";

var sIndexOf = "!";

function ReceiveServerData(sValue)

{

var arrValue = Array();

arrValue = sValue.split(_Split);

document.getElementById(arrValue[0]).innerHTML = arrValue[1];

document.getElementById(arrValue[2]).innerHTML = arrValue[3];

fillHidden(arrValue[4],arrValue[6],arrValue[7]);

fillHidden(arrValue[5],arrValue[8],arrValue[9]);

}

//-------------------------------------------------------

function ButtonHTML_onclick(ListBoxFrom,ListBoxTo,

HiddenToText,HiddenToValue,

HiddenFromText,HiddenFromValue,

bDoFromList)

{

var sListBox;

var iSelectedIndex;

if (typeof(bDoFromList)== "undefined")

{

bDoFromList=true;

}

else

{if (typeof(bDoFromList)!= "boolean")

{

bDoFromList=true;

}

}

if (bDoFromList)

{

sListBox="ListBoxFrom";

}

else

{

sListBox = "ListBoxTo";

}

eval("iSelectedIndex="+sListBox+".selectedIndex");

CallTheServer(iSelectedIndex + sIndexOf +

bDoFromList + sIndexOf +

HiddenFromText.value + sIndexOf +

HiddenFromValue.value + sIndexOf +

HiddenToText.value + sIndexOf +

HiddenToValue.value );

}

//-------------------------------------------------------

function fillHidden (ListBox,HiddenText,HiddenValue)

{

var iOption;

var sHelp = "";

var iHelp= "";

var sHiddenText = "";

var sHiddenValue = "";

eval("iOption= "+ListBox+".length");

hiddenClear(HiddenText,HiddenValue);

for (var i=0 ;i<iOption; i++)

{

eval("sHelp="+ListBox+".item(i).text");

eval("iHelp="+ListBox+".item(i).value");

sHiddenText = sHiddenText + sHelp ;

sHiddenValue = sHiddenValue + iHelp;

if (i != iOption - 1)

{

sHiddenText = sHiddenText + _Split;

sHiddenValue = sHiddenValue + _Split;

};

};

eval(HiddenText+".value = sHiddenText");

eval(HiddenValue+".value = sHiddenValue");

}

//-------------------------------------------------------

function hiddenClear(HiddenText,HiddenValue)

{

var s = "";

eval(HiddenText+".value = s");

eval(HiddenValue+".value = s");

}

// ]]>

</script>

Now we can test our control. With this purposes we reaped the actions done in the article, run the project, choose ListBoxes_s (fig. 4)

and.....receive the result as though property C_Client of the ListBoxesFT_C has been set to "true" in spite of the fact that we used server methods (this is without any re-creating and flicker of the page !!!).

CONCLUSION

In two series of the multi-part articles we discussed three different approaches of building the Web User Control. As example we have chosen the control, which carries out identical functions. It has helped us to concentrate on the mechanism of data exchange (server, client or Client Callbacks mechanism).

I hope that two series of these articles will help you to choose your own way (depending on your requests) to build web user control in Visual Studio 2005.

Good luck in programming !