C - Fill a combo box with a DataTable

Question

I m used to work with Java where large amounts of examples are available  For various reasons I had to switch to C  and trying to do the following in SharpDevelop      Form has a menu containing a combobox added via SharpDevelop s GUI     --- Variables languages   new string 2   languages 0     English   languages 1     German   DataSet myDataSet   new DataSet        --- Preparation DataTable lTable   new DataTable  Lang    DataColumn lName   new DataColumn  Language   typeof string    lTable Columns Add  lName    for  int i 0  i lt languages Length  i           DataRow lLang   lTable NewRow        lLang  Language     languages i       lTable Rows Add lLang     myDataSet Tables Add lTable       --- Handling the combobox mnuActionLanguage ComboBox DataSource   myDataSet Tables  Lang   DefaultView  mnuActionLanguage ComboBox DisplayMember    Language     One would assume to see some values in the dropdown  but it s empty  Please tell me what I m doing wrong     EDIT  mnuActionLanguage ComboBox DataBind   is what I also found on the net  but it doesn t work in my case   SOLUTION  mnuActionLanguage ComboBox BindingContext   this BindingContext    at the end solved the problem

User · Answer

A few points   1   DataBind    is only for web apps  not windows apps    2  Your code looks very  JAVAish   not a bad thing  just an observation    Try this   mnuActionLanguage ComboBox DataSource   languages    If that doesn t work    then I m assuming that your datasource is being stepped on somewhere else in the code

User · Answer

Are you applying a RowFilter to your DefaultView later in the code  This could change the results returned   I would also avoid using the string as the display member if you have a direct reference the the data column I would use the object properties   mnuActionLanguage ComboBox DataSource   lTable DefaultView  mnuActionLanguage ComboBox DisplayMember   lName ColumnName   I have tried this with a blank form and standard combo  and seems to work for me

User · Answer

string strConn    Data Source SEZSW08 Initial Catalog Nidhi Integrated Security True   SqlConnection Con   new SqlConnection strConn   Con Open    string strCmd    select companyName from companyinfo where CompanyName      cmbCompName SelectedValue         SqlDataAdapter da   new SqlDataAdapter strCmd  Con   DataSet ds   new DataSet    Con Close    da Fill ds   cmbCompName DataSource   ds  cmbCompName DisplayMember    CompanyName   cmbCompName ValueMember    CompanyName     cmbCompName DataBind    cmbCompName Enabled   true

User · Answer

You need to set the binding context of the ToolStripComboBox ComboBox   Here is a slightly modified version of the code that I have just recreated using Visual Studio  The menu item combo box is called toolStripComboBox1 in my case  Note the last line of code to set the binding context   I noticed that if the combo is in the visible are of the toolstrip  the binding works without this but not when it is in a drop-down  Do you get the same problem   If you can t get this working  drop me a line via my contact page and I will send you the project  You won t be able to load it using SharpDevelop but will with C  Express   var languages   new string 2   languages 0     English   languages 1     German    DataSet myDataSet   new DataSet        --- Preparation DataTable lTable   new DataTable  Lang    DataColumn lName   new DataColumn  Language   typeof string    lTable Columns Add lName    for  int i   0  i  lt  languages Length  i          DataRow lLang   lTable NewRow        lLang  Language     languages i       lTable Rows Add lLang     myDataSet Tables Add lTable    toolStripComboBox1 ComboBox DataSource   myDataSet Tables  Lang   DefaultView  toolStripComboBox1 ComboBox DisplayMember    Language    toolStripComboBox1 ComboBox BindingContext   this BindingContext

User · Answer

You need to set the binding context of the ToolStripComboBox ComboBox   Here is a slightly modified version of the code that I have just recreated using Visual Studio  The menu item combo box is called toolStripComboBox1 in my case  Note the last line of code to set the binding context   I noticed that if the combo is in the visible are of the toolstrip  the binding works without this but not when it is in a drop-down  Do you get the same problem   If you can t get this working  drop me a line via my contact page and I will send you the project  You won t be able to load it using SharpDevelop but will with C  Express   var languages   new string 2   languages 0     English   languages 1     German    DataSet myDataSet   new DataSet        --- Preparation DataTable lTable   new DataTable  Lang    DataColumn lName   new DataColumn  Language   typeof string    lTable Columns Add lName    for  int i   0  i  lt  languages Length  i          DataRow lLang   lTable NewRow        lLang  Language     languages i       lTable Rows Add lLang     myDataSet Tables Add lTable    toolStripComboBox1 ComboBox DataSource   myDataSet Tables  Lang   DefaultView  toolStripComboBox1 ComboBox DisplayMember    Language    toolStripComboBox1 ComboBox BindingContext   this BindingContext

User · Answer

string strConn    Data Source SEZSW08 Initial Catalog Nidhi Integrated Security True   SqlConnection Con   new SqlConnection strConn   Con Open    string strCmd    select companyName from companyinfo where CompanyName      cmbCompName SelectedValue         SqlDataAdapter da   new SqlDataAdapter strCmd  Con   DataSet ds   new DataSet    Con Close    da Fill ds   cmbCompName DataSource   ds  cmbCompName DisplayMember    CompanyName   cmbCompName ValueMember    CompanyName     cmbCompName DataBind    cmbCompName Enabled   true

User · Answer

This line  mnuActionLanguage ComboBox DisplayMember    Lang Language     is wrong  Change it to  mnuActionLanguage ComboBox DisplayMember    Language     and it will work  even without DataBind

User · Answer

You need to set the binding context of the ToolStripComboBox ComboBox   Here is a slightly modified version of the code that I have just recreated using Visual Studio  The menu item combo box is called toolStripComboBox1 in my case  Note the last line of code to set the binding context   I noticed that if the combo is in the visible are of the toolstrip  the binding works without this but not when it is in a drop-down  Do you get the same problem   If you can t get this working  drop me a line via my contact page and I will send you the project  You won t be able to load it using SharpDevelop but will with C  Express   var languages   new string 2   languages 0     English   languages 1     German    DataSet myDataSet   new DataSet        --- Preparation DataTable lTable   new DataTable  Lang    DataColumn lName   new DataColumn  Language   typeof string    lTable Columns Add lName    for  int i   0  i  lt  languages Length  i          DataRow lLang   lTable NewRow        lLang  Language     languages i       lTable Rows Add lLang     myDataSet Tables Add lTable    toolStripComboBox1 ComboBox DataSource   myDataSet Tables  Lang   DefaultView  toolStripComboBox1 ComboBox DisplayMember    Language    toolStripComboBox1 ComboBox BindingContext   this BindingContext

User · Answer

A few points   1   DataBind    is only for web apps  not windows apps    2  Your code looks very  JAVAish   not a bad thing  just an observation    Try this   mnuActionLanguage ComboBox DataSource   languages    If that doesn t work    then I m assuming that your datasource is being stepped on somewhere else in the code

User · Answer

This line  mnuActionLanguage ComboBox DisplayMember    Lang Language     is wrong  Change it to  mnuActionLanguage ComboBox DisplayMember    Language     and it will work  even without DataBind

User · Answer

A few points   1   DataBind    is only for web apps  not windows apps    2  Your code looks very  JAVAish   not a bad thing  just an observation    Try this   mnuActionLanguage ComboBox DataSource   languages    If that doesn t work    then I m assuming that your datasource is being stepped on somewhere else in the code

User · Answer

A few points   1   DataBind    is only for web apps  not windows apps    2  Your code looks very  JAVAish   not a bad thing  just an observation    Try this   mnuActionLanguage ComboBox DataSource   languages    If that doesn t work    then I m assuming that your datasource is being stepped on somewhere else in the code

User · Answer

Are you applying a RowFilter to your DefaultView later in the code  This could change the results returned   I would also avoid using the string as the display member if you have a direct reference the the data column I would use the object properties   mnuActionLanguage ComboBox DataSource   lTable DefaultView  mnuActionLanguage ComboBox DisplayMember   lName ColumnName   I have tried this with a blank form and standard combo  and seems to work for me

User · Answer

You need to set the binding context of the ToolStripComboBox ComboBox   Here is a slightly modified version of the code that I have just recreated using Visual Studio  The menu item combo box is called toolStripComboBox1 in my case  Note the last line of code to set the binding context   I noticed that if the combo is in the visible are of the toolstrip  the binding works without this but not when it is in a drop-down  Do you get the same problem   If you can t get this working  drop me a line via my contact page and I will send you the project  You won t be able to load it using SharpDevelop but will with C  Express   var languages   new string 2   languages 0     English   languages 1     German    DataSet myDataSet   new DataSet        --- Preparation DataTable lTable   new DataTable  Lang    DataColumn lName   new DataColumn  Language   typeof string    lTable Columns Add lName    for  int i   0  i  lt  languages Length  i          DataRow lLang   lTable NewRow        lLang  Language     languages i       lTable Rows Add lLang     myDataSet Tables Add lTable    toolStripComboBox1 ComboBox DataSource   myDataSet Tables  Lang   DefaultView  toolStripComboBox1 ComboBox DisplayMember    Language    toolStripComboBox1 ComboBox BindingContext   this BindingContext

User · Answer

This line  mnuActionLanguage ComboBox DisplayMember    Lang Language     is wrong  Change it to  mnuActionLanguage ComboBox DisplayMember    Language     and it will work  even without DataBind

User · Answer

Are you applying a RowFilter to your DefaultView later in the code  This could change the results returned   I would also avoid using the string as the display member if you have a direct reference the the data column I would use the object properties   mnuActionLanguage ComboBox DataSource   lTable DefaultView  mnuActionLanguage ComboBox DisplayMember   lName ColumnName   I have tried this with a blank form and standard combo  and seems to work for me

User · Answer

For example  i created a table    DataTable dt   new DataTable     dt Columns Add  Title   typeof string    dt Columns Add  Value   typeof int      Add recorde to table    DataRow row   dt NewRow    row  Title      Price  row  Value     2000  dt Rows Add row     or    dt Rows Add  Price  2000     finally    combo DataSource   dt  combo DisplayMember    Title   combo ValueMember    Value

User · Answer

For example  i created a table    DataTable dt   new DataTable     dt Columns Add  Title   typeof string    dt Columns Add  Value   typeof int      Add recorde to table    DataRow row   dt NewRow    row  Title      Price  row  Value     2000  dt Rows Add row     or    dt Rows Add  Price  2000     finally    combo DataSource   dt  combo DisplayMember    Title   combo ValueMember    Value

User · Answer

Are you applying a RowFilter to your DefaultView later in the code  This could change the results returned   I would also avoid using the string as the display member if you have a direct reference the the data column I would use the object properties   mnuActionLanguage ComboBox DataSource   lTable DefaultView  mnuActionLanguage ComboBox DisplayMember   lName ColumnName   I have tried this with a blank form and standard combo  and seems to work for me

User · Answer

This line  mnuActionLanguage ComboBox DisplayMember    Lang Language     is wrong  Change it to  mnuActionLanguage ComboBox DisplayMember    Language     and it will work  even without DataBind

[c#] C# - Fill a combo box with a DataTable

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