Preselecting item in CascadingDropDown from the values in the database

I have a control that you select the state, city, zip. This is then stored in the database. When I want to edit that record, I want it to select the item from the value in the database. How can I accomplish this.

Example:

ID STATE CITY ZIP
0 PA PERKASIE 18944

Gets inserted into database. When editing ID 0, it needs to preselect PA, PERKASIE, 18944 in the cascading drop downs.

Hi,

You can specify a default item in the method that fills the DDL.

And the problem is how to determine which item should be the default one. I think you can keep the information of it in session, when the user clicks a button to start editing. For example:

void btnEdit_Click()

{

CascadingDropDown2.ContextKey = "the value of the item to be preselected";

}

public AjaxControlToolkit.CascadingDropDownNameValue[] GetDropDownContents(
string knownCategoryValues, string category, string contextKey)
{
AjaxControlToolkit.CascadingDropDownNameValue[] result = new AjaxControlToolkit.CascadingDropDownNameValue[10];
for (int i = 0; i < 10; i++)
{
result[i] = new AjaxControlToolkit.CascadingDropDownNameValue();
result[i].name = i.ToString() + " " + category + " of " + knownCategoryValues + "name";
result[i].value = i.ToString() + " " + category + " of " + knownCategoryValues + "value";

if(result[i] == contextKey) result[i].isDefaultValue = true;
}
return result;
}

Hope this helps.

Putting this somewhere in the page initialization might work, too:

MyCascadingStateDropDown1.SelectedValue = mystateid;

This seems to invoke the WebMethod to prepopulate the list, preselect the default, and invoke the cascade.

Yes, this help!

I am using the CascadingDropDownList control for two DropDownList I have on my page. The first is a GroupType and the seccond is a Group. I hvae this all working with loading the data from the WebService. All works great except for when I try to go into the Edit Mode. In Edit Mode, I need to set the two DropDwonList with the items the user selected in edit mode.

Here is a section of my code from the C# side of things where I am trying to set the ContextKey...

CascadingDropDownGroupType.ContextKey = dr2["GRPLKUPiGroupType"].ToString();

CascadingDropDownGroup.ContextKey = dr2["GRPLKUPsGroupCode"].ToString();

Here is my WebService Code... (I have included the complete WebService) Keep in mind the WebService works fine, I just need to know where / how to set the items I want to display as SELECTED in the DDL when the user goes into EDIT MODE.

using System;

using System.Web;

using System.Collections;

using System.Collections.Generic;

using System.Collections.Specialized;

using System.Web.Services;

using System.Web.Services.Protocols;

using System.Web.SessionState;

using AjaxControlToolkit;

using System.Data;

using System.Data.SqlClient;

using System.Web.Script.Services;

using boyce;

///<summary>

///</summary>

[WebService(Namespace ="http://tempuri.org/")]

[WebServiceBinding(ConformsTo =WsiProfiles.BasicProfile1_1)]

[System.Web.Script.Services.ScriptService]

publicclassBoyceWebService : System.Web.Services.WebService

{

public BoyceWebService()

{

//Uncomment the following line if using designed components

//InitializeComponent();

}

[WebMethod(true)]publicCascadingDropDownNameValue[] GetTheGroupTypes(string knownCategoryValues,string category)

{

string[] sArray =newstring[10];

SessionManager CurrentSession;

CurrentSession =SessionManager.GetSessionInfo();

if (CurrentSession !=null)

{

category = CurrentSession.iSelectedGroupTypeId.ToString();

}

else

{

System.Diagnostics.Debug.WriteLine("GetTheGroupTypes -- Session NULL");

}

string DSN = System.Configuration.ConfigurationManager.ConnectionStrings["SchoolFinancialConnectionString1"].ToString();

DataSet ds =newDataSet();

object oSTRUCT =newobject();

string sSQL =string.Empty;

DataCallManager.InitArray();

sArray[0] =string.Empty;

sArray[1] ="-1";

sArray[2] =string.Empty;

sSQL =DataCall.GetSQL("tblLookupGroupTypes_T","S9", sArray, oSTRUCT);SqlConnection cn =newSqlConnection(DSN);

cn.Open();

SqlDataAdapter dscmd =newSqlDataAdapter(sSQL, cn);

dscmd.Fill(ds,"DCM_Get");

List<CascadingDropDownNameValue> values =newList<CascadingDropDownNameValue>();

if (ds.Tables.Count != 0)

{

foreach (DataRow drLOOPin ds.Tables[0].Rows)

{

string sTheGroupType = (string)drLOOP["GRPTYPsGroupType"];

int iTheGroupTypeId = (int)drLOOP["GRPTYPiID"];

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString()));

}

}

cn.Close();

dscmd.Dispose();

cn.Dispose();

return values.ToArray();

}

[WebMethod(true)]publicCascadingDropDownNameValue[] GetTheGroupsForTheGroupType(string knownCategoryValues,string category)

{

StringDictionary kv =CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);

int iTheGroupTypeId = -1;if (!kv.ContainsKey("GroupType") || !Int32.TryParse(kv["GroupType"],out iTheGroupTypeId))

{

returnnull;

}

string[] sArray =newstring[10];

string DSN = System.Configuration.ConfigurationManager.ConnectionStrings["SchoolFinancialConnectionString1"].ToString();

DataSet ds =newDataSet();

object oSTRUCT =newobject();

string sSQL =string.Empty;

DataCallManager.InitArray();

sArray[0] =Convert.ToString(iTheGroupTypeId);

sArray[1] ="-1";

sArray[2] =string.Empty;

sSQL =DataCall.GetSQL("tblLookupGroupTypes_T","S10", sArray, oSTRUCT);SqlConnection cn =newSqlConnection(DSN);

cn.Open();

SqlDataAdapter dscmd =newSqlDataAdapter(sSQL, cn);

dscmd.Fill(ds,"DCM_Get");

List<CascadingDropDownNameValue> values =newList<CascadingDropDownNameValue>();

if (ds.Tables.Count != 0)

{

foreach (DataRow drLOOPin ds.Tables[0].Rows)

{

values.Add(newCascadingDropDownNameValue((string)drLOOP["GRPLKUPsGroupName"], drLOOP["GRPLKUPiID"].ToString()));

}

}

cn.Close();

dscmd.Dispose();

cn.Dispose();

return values.ToArray();

}

}

I figured this one out.. All you have to do is in the WebService add / replace the values add with the following

if (Convert.ToInt32(CurrentSession.iSelectedGroupTypeId.ToString()) == iTheGroupTypeId)

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),true));

}

else

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),false));

}

Does anybody know then why setting the isDefaultValue (the third parameter to the constructor of CascadingDropDownNameValue) doesn't do anything? I have debugged my page to confirm that I am indeed setting that value however when the webmethod returns the results it always selects the first value.

Any help would be greatly appreciated.

Thanks,

I did get this to work, and here is the complete WebService I used. Now keep in mind that some of the code will not apply as it references our data access layer we use. However the part you are asking about is there and working. You basically set the "contextKey" inside your normal code and then the web service has to be modified to pass that "contextKey" in. From there, you use the value of the "contextKey" to know if you should set the DefaultValue or not.

In your code, when the page is loaded, you set the value of the context key to what your DEFAULT VALUES are to be. In my example, I have a DDL for GROUP TYPE and a DDL for GROUP.

CascadingDropDownGroupType.ContextKey = dr2["GRPLKUPiGroupType"].ToString();

CascadingDropDownGroup.ContextKey = dr2["GRPLKUPsGroupCode"].ToString();

==================================================================================

Here is the WebService Code.....

==================================================================================

using System;

using System.Web;

using System.Collections;

using System.Collections.Generic;

using System.Collections.Specialized;

using System.Web.Services;

using System.Web.Services.Protocols;

using System.Web.SessionState;

using AjaxControlToolkit;

using System.Data;

using System.Data.SqlClient;

using System.Web.Script.Services;

using boyce;

///<summary>

///</summary>[WebService(Namespace ="http://tempuri.org/")]

[WebServiceBinding(ConformsTo =WsiProfiles.BasicProfile1_1)]

[System.Web.Script.Services.ScriptService]

publicclassBoyceWebService : System.Web.Services.WebService

{

public BoyceWebService()

{

//Uncomment the following line if using designed components

//InitializeComponent();

}

[WebMethod(true)]publicCascadingDropDownNameValue[] GetTheGroupTypes(string knownCategoryValues,string category,string contextKey)

{

string[] sArray =newstring[10];

SessionManager CurrentSession;

CurrentSession =SessionManager.GetSessionInfo();

string DSN = System.Configuration.ConfigurationManager.ConnectionStrings["SchoolFinancialConnectionString1"].ToString();

DataSet ds =newDataSet();

object oSTRUCT =newobject();

string sSQL =string.Empty;

DataCallManager.InitArray();

sArray[0] = CurrentSession.sSelectedGroupScreenTYPE;

sArray[1] = contextKey.ToString();

sSQL =DataCall.GetSQL("tblLookupGroupTypes_T","S9", sArray, oSTRUCT);SqlConnection cn =newSqlConnection(DSN);

cn.Open();

SqlDataAdapter dscmd =newSqlDataAdapter(sSQL, cn);

dscmd.Fill(ds,"DCM_Get");

List<CascadingDropDownNameValue> values =newList<CascadingDropDownNameValue>();

if (ds.Tables.Count != 0)

{

foreach (DataRow drLOOPin ds.Tables[0].Rows)

{

string sTheGroupType = (string)drLOOP["GRPTYPsGroupType"];

int iTheGroupTypeId = (int)drLOOP["GRPTYPiID"];

if (contextKey.ToString().Trim() !=string.Empty || contextKey.ToString().Trim() !="-1")

{

if (Convert.ToInt32(contextKey.ToString()) == iTheGroupTypeId)

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),true));

}

else

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),false));

}

}

else

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString()));

}

}

}

cn.Close();

dscmd.Dispose();

cn.Dispose();

return values.ToArray();

}

[WebMethod(true)]publicCascadingDropDownNameValue[] GetTheGroupsForTheGroupType(string knownCategoryValues,string category,string contextKey)

{

StringDictionary kv =CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);

int iTheGroupTypeId = -1;if (!kv.ContainsKey("GroupType") || !Int32.TryParse(kv["GroupType"],out iTheGroupTypeId))

{

returnnull;

}

string[] sArray =newstring[10];

string DSN = System.Configuration.ConfigurationManager.ConnectionStrings["SchoolFinancialConnectionString1"].ToString();

DataSet ds =newDataSet();

object oSTRUCT =newobject();

string sSQL =string.Empty;

DataCallManager.InitArray();sArray[0] =Convert.ToString(iTheGroupTypeId);

sArray[1] = contextKey.ToString();

sSQL =DataCall.GetSQL("tblLookupGroupTypes_T","S10", sArray, oSTRUCT);

SqlConnection cn =newSqlConnection(DSN);

cn.Open();

SqlDataAdapter dscmd =newSqlDataAdapter(sSQL, cn);

dscmd.Fill(ds,"DCM_Get");

List<CascadingDropDownNameValue> values =newList<CascadingDropDownNameValue>();if (ds.Tables.Count != 0)

{

foreach (DataRow drLOOPin ds.Tables[0].Rows)

{

if (contextKey.ToString().Trim() !=string.Empty || contextKey.ToString().Trim() !="-1")

{

if (drLOOP["GRPLKUPsGroupCode"].ToString() == contextKey.ToString())

{

values.Add(newCascadingDropDownNameValue(

(string)drLOOP["GRPLKUPsGroupName"], drLOOP["GRPLKUPsGroupCode"].ToString(),true));

}

else

{

values.Add(newCascadingDropDownNameValue((string)drLOOP["GRPLKUPsGroupName"], drLOOP["GRPLKUPsGroupCode"].ToString(),false));

}

}

else

{

values.Add(newCascadingDropDownNameValue((string)drLOOP["GRPLKUPsGroupName"], drLOOP["GRPLKUPsGroupCode"].ToString()));

}

}

}

cn.Close();

dscmd.Dispose();

cn.Dispose();

return values.ToArray();

}

}

I have no idea what happened to my last post.. SORRY.. Here is the WebService code...

using System;

using System.Web;

using System.Collections;

using System.Collections.Generic;

using System.Collections.Specialized;

using System.Web.Services;

using System.Web.Services.Protocols;

using System.Web.SessionState;

using AjaxControlToolkit;

using System.Data;

using System.Data.SqlClient;

using System.Web.Script.Services;

using boyce;

///<summary>

///</summary>[WebService(Namespace ="http://tempuri.org/")]

[WebServiceBinding(ConformsTo =WsiProfiles.BasicProfile1_1)]

[System.Web.Script.Services.ScriptService]

publicclassBoyceWebService : System.Web.Services.WebService

{

public BoyceWebService()

{

//Uncomment the following line if using designed components

//InitializeComponent();

}

[WebMethod(true)]publicCascadingDropDownNameValue[] GetTheGroupTypes(string knownCategoryValues,string category,string contextKey)

{

string[] sArray =newstring[10];

SessionManager CurrentSession;

CurrentSession =SessionManager.GetSessionInfo();

string DSN = System.Configuration.ConfigurationManager.ConnectionStrings["SchoolFinancialConnectionString1"].ToString();

DataSet ds =newDataSet();

object oSTRUCT =newobject();

string sSQL =string.Empty;

DataCallManager.InitArray();

sArray[0] = CurrentSession.sSelectedGroupScreenTYPE;

sArray[1] = contextKey.ToString();

sSQL =DataCall.GetSQL("tblLookupGroupTypes_T","S9", sArray, oSTRUCT);SqlConnection cn =newSqlConnection(DSN);

cn.Open();

SqlDataAdapter dscmd =newSqlDataAdapter(sSQL, cn);

dscmd.Fill(ds,"DCM_Get");

List<CascadingDropDownNameValue> values =newList<CascadingDropDownNameValue>();

if (ds.Tables.Count != 0)

{

foreach (DataRow drLOOPin ds.Tables[0].Rows)

{

string sTheGroupType = (string)drLOOP["GRPTYPsGroupType"];

int iTheGroupTypeId = (int)drLOOP["GRPTYPiID"];

if (contextKey.ToString().Trim() !=string.Empty || contextKey.ToString().Trim() !="-1")

{

if (Convert.ToInt32(contextKey.ToString()) == iTheGroupTypeId)

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),true));

}

else

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),false));

}

}

else

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString()));

}

}

}

cn.Close();

dscmd.Dispose();

cn.Dispose();

return values.ToArray();

}

[WebMethod(true)]publicCascadingDropDownNameValue[] GetTheGroupsForTheGroupType(string knownCategoryValues,string category,string contextKey)

{

StringDictionary kv =CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);

int iTheGroupTypeId = -1;if (!kv.ContainsKey("GroupType") || !Int32.TryParse(kv["GroupType"],out iTheGroupTypeId))

{

returnnull;

}

string[] sArray =newstring[10];

string DSN = System.Configuration.ConfigurationManager.ConnectionStrings["SchoolFinancialConnectionString1"].ToString();

DataSet ds =newDataSet();

object oSTRUCT =newobject();

string sSQL =string.Empty;

DataCallManager.InitArray();sArray[0] =Convert.ToString(iTheGroupTypeId);

sArray[1] = contextKey.ToString();

sSQL =DataCall.GetSQL("tblLookupGroupTypes_T","S10", sArray, oSTRUCT);

SqlConnection cn =newSqlConnection(DSN);

cn.Open();

SqlDataAdapter dscmd =newSqlDataAdapter(sSQL, cn);

dscmd.Fill(ds,"DCM_Get");

List<CascadingDropDownNameValue> values =newList<CascadingDropDownNameValue>();if (ds.Tables.Count != 0)

{

foreach (DataRow drLOOPin ds.Tables[0].Rows)

{

if (contextKey.ToString().Trim() !=string.Empty || contextKey.ToString().Trim() !="-1")

{

if (drLOOP["GRPLKUPsGroupCode"].ToString() == contextKey.ToString())

{

values.Add(newCascadingDropDownNameValue(

(string)drLOOP["GRPLKUPsGroupName"], drLOOP["GRPLKUPsGroupCode"].ToString(),true));

}

else

{

values.Add(newCascadingDropDownNameValue((string)drLOOP["GRPLKUPsGroupName"], drLOOP["GRPLKUPsGroupCode"].ToString(),false));

}

}

else

{

values.Add(newCascadingDropDownNameValue((string)drLOOP["GRPLKUPsGroupName"], drLOOP["GRPLKUPsGroupCode"].ToString()));

}

}

}

cn.Close();

dscmd.Dispose();

cn.Dispose();

return values.ToArray();

}

}

Hmmm. I am not using a context key but I am still conditionally adding the true parameter to the new cascadingdropdownvalue. Also, from my understanding of its constructor, isDefaultValue defaults to false if a bool is not passed. Below is my code, I am using the selected value from the previous dropdownlist to try and set the selected value of this drop down list. (And yes, the previous dropdownlist has the same elements in it as this one does).

Thanks for responding.

[WebMethod]public static CascadingDropDownNameValue[] GetTestKeys(string knownCategoryValues,string category) {StringDictionary kv = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);if (!kv.ContainsKey("officeType") || String.IsNullOrEmpty(kv["officeType"])) {return null;}OracleCommand cmdGetTestKeys =new OracleCommand(@."SELECT test_key, test_key || ' ' || test_orgn || ' ' || test_subj as description FROM linc.pccdb_ttestWHERE test_user = :p_OfficeORDER BY test_key",new OracleConnection(ConfigurationManager.ConnectionStrings["PCCDB_Web"].ConnectionString));cmdGetTestKeys.Parameters.AddWithValue("p_Office", kv["officeType"]);cmdGetTestKeys.Connection.Open();OracleDataReader drTestKeys = cmdGetTestKeys.ExecuteReader();List values =new List();Object[] keyValuePair =new Object[2];string value = String.Empty;while (drTestKeys.Read() ==true) {drTestKeys.GetValues(keyValuePair);value = Convert.ToInt32(keyValuePair[0]).ToString();//Check for the headerTestKey, if it exits then popluate the set for the header,//otherwise setup the detail test key to match the headerTestKey.if (!kv.ContainsKey("headerTestKey") || String.IsNullOrEmpty(kv["headerTestKey"])) {values.Add(new CascadingDropDownNameValue((string)keyValuePair[1],value));}else {if (value == kv["headerTestKey"]) {values.Add(new CascadingDropDownNameValue((string)keyValuePair[1],value,true));}else {values.Add(new CascadingDropDownNameValue((string)keyValuePair[1],value));}}}cmdGetTestKeys.Connection.Close();return values.ToArray();}

From the initial look at your code, I would agree, it should work fine.

One thing I ran into, and fought for days because I was "SURE" I had it correct, was the key names. You may want to consider placing some debug statements around the "IF/ELSE" logic to see exactly what part of the code is being hit. I placed some breakpoints in my code and examined the key collection. I found I was looking for the incorrect key name and thus never hitting the code I was thinking it was hitting. I know that sounds basic, but from looking at your code it should work, due to the fact it is not working, I am guessing it may not be hitting the code you expect.

I would examine the flow around this section and make 100% sure the key you are looking for "headerTestKey" really exists in the key collection.

If this does not work, post you entire webserice and I will take a look at it and try to recreate the problem on my side.

Good Luck...

if (!kv.ContainsKey("headerTestKey") || String.IsNullOrEmpty(kv["headerTestKey"])) {
values.Add(new CascadingDropDownNameValue((string)keyValuePair[1],value));
}
else {
if (value == kv["headerTestKey"]) {
values.Add(new CascadingDropDownNameValue((string)keyValuePair[1],value,true));
}
else {
values.Add(new CascadingDropDownNameValue((string)keyValuePair[1],value));
}
}

this almost works for me. Almost...

I have a gridview on my page and when i click on edit command of gridview row, three dropdowns have to be populated with default value based on row data.

So gridview_rowediting is called firstly. I declare contextkeys for all of my dropdowns here.

Next, WebMethods do their job. I found out they do it properly while debbuging.

But the problem is that only first time calling "edit" this works. Then there are always same items choosen. Seems strange because webmethods do their job.

What could be wrong?

Some things you may try... (You may have already tried these items)

1. Make sure each time your gridview_rowediting fires, that the context keys are being set with the values you are expecting. I knwo, from working with GridViews in the past, that you have to be careful to get the correct row values.

CascadingDropDownGroupType.ContextKey = dr2["GRPLKUPiGroupType"].ToString();

CascadingDropDownGroup.ContextKey = dr2["GRPLKUPsGroupCode"].ToString();

2. Once you have verified the ContextKeys are being set properly, make sure the are correctly set inside the WebMethod. Just to make sure nothing got hosed up in the passing of the ContextKeys.

Just display / examine thecontextKey.ToString().Trim() to make sure each of them are properly set based on the data from the row edit.

3. Make sure you aer setting the DEFAULT VALUE is TRUE for the matching ContextKey Value.

if (Convert.ToInt32(contextKey.ToString()) == iTheGroupTypeId)

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),true));

}

else

{

values.Add(newCascadingDropDownNameValue(sTheGroupType, iTheGroupTypeId.ToString(),false));

}

4. Make sure the values passed from one WebMethod to the other is set / used correctly. For example, I have 2 CDDL in my code. One is Group Type and the other is Group. In the 2nd WebMethod I use the following to get the value passed from the 1st WebMethod. Verify you have this set in your code from WebMethod to WebMethod and make sure the highlighted items "out" is being set correctly.

StringDictionary kv =CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues);

int iTheGroupTypeId = -1;

if (!kv.ContainsKey("GroupType") || !Int32.TryParse(kv["GroupType"],out iTheGroupTypeId))

{

returnnull;

}

I hope this helps.. If not, post your complete WebService code and I will do what I can to try and look at it and help you out.

Best of Luck...

As I said, i debbuged the web service and checked all these things. There are no problems with contexKey - it allways holds the value needed. So the code

For Each row As DataRow In gds.Tables(0).Rows
If cint(row("id_project")) = cint(contextKey) Then
values.Add(New CascadingDropDownNameValue( _
row("name"), row("id_project"), True))
Else
values.Add(New CascadingDropDownNameValue( _
row("name"), row("id_project"), False))
End If
Next

always "finds" the item needed. It's just not displayed then...

it works now. I had to put

dropdownlist.SelectedValue = -1

for all my dropdowns in datagrid_RowEditing sub