I just bound my combobox to database but it is not showing me values. However, I can see by the length of dropdown box that values are in it but aren't visible.
I just clicked on a value and it did work and took me to the next form. But how can I make those values visible?
private void StudentLogin_Load(object sender, EventArgs e)
{
con = new SqlConnection(constr);
con.Open();
cmd = new SqlCommand("select Std_ID from Student", con);
SqlDataReader reader;
reader = cmd.ExecuteReader();
DataTable dt = new DataTable();
dt.Columns.Add("Std_ID", typeof(string));
dt.Columns.Add("Name", typeof(string));
dt.Load(reader);
metroComboBox1.ValueMember = "Std_ID";
metroComboBox1.DisplayMember = "Name";
metroComboBox1.DataSource = dt;
con.Close();
}
private void metroComboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
string ID = metroComboBox1.SelectedValue.ToString();
}
metroComboBox1.DataSource = dt;
metroComboBox1.ValueMember = "Std_ID";
metroComboBox1.DisplayMember = "Name";
metroComboBox1.DataBind();
I think the problem is in your query:
cmd = new SqlCommand("select Std_ID from Student", con);
does not contain the name. Instead try the following:
cmd = new SqlCommand("select Std_ID, Name from Student", con);
In order to display the ID instead of the name, put Std_ID as displaymamber as well.
Related
// fill from database
SqlConnection cn = new SqlConnection(GlobalData.connectionstring);
string readnamesquery = "select cwFullTitle from tbCowWorkers";
cn.Open();
SqlCommand cmd = new SqlCommand(readnamesquery, cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
ddlUsers.DataSource = dt;
ddlUsers.DataValueField = "cwFullTitle";
ddlUsers.DataTextField = "cwFullTitle";
ddlUsers.DataBind();
cn.Close();
// insert selected value to database
SqlConnection cn = new SqlConnection(GlobalData.connectionstring);
string registerQuery = "insert into Depot (dTdeliveryName) values (N'"+ddlUsers.SelectedValue.ToString()+"')";
SqlCommand cmd = new SqlCommand(registerQuery, cn);
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
I fill a Dropdownlist from SQL Server, then send selected item to another table in SQL Server; but it send first item of Dropdownlist as selected item.
Selected item didn't change and returns default value.
The reason is obvious, you are filling the dropdown list and then inserting the record, so it is bound to take the first item of the DropdownList.
I would suggest you separate the code of filling the dropdown list in another function and do the insertion only on selected_index change (ddl_SelectedIndexChanged) of DropDownList. In this ddl_SelectedIndexChanged function just check the selected value of the drop-down list and insert it to your target table (please remember to not invoke the call the function to load/Fill Dropdown List which you are currently doing in the shared code snippet).
SomeThing Like this
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
SqlConnection cn = new SqlConnection(GlobalData.connectionstring);
string readnamesquery = "select cwFullTitle from tbCowWorkers";
cn.Open();
SqlCommand cmd = new SqlCommand(readnamesquery, cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
ddlUsers.DataSource = dt;
ddlUsers.DataValueField = "cwFullTitle";
ddlUsers.DataTextField = "cwFullTitle";
ddlUsers.DataBind();
cn.Close();
}
}
protected void ddlUser_SelectedIndexChanged(object sender, EventArgs e)
{
// insert selected value to database
SqlConnection cn = new SqlConnection(GlobalData.connectionstring);
string registerQuery = "insert into Depot (dTdeliveryName) values
(N'"+ddlUsers.SelectedValue.ToString()+"')";
SqlCommand cmd = new SqlCommand(registerQuery, cn);
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}
Hope this Helps!
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
//Loading Dropdown by calling This.
LoadDdl();
}
}
//Load Dropdown From Database.
protected void LoadDdl(){
SqlConnection cn = new SqlConnection(GlobalData.connectionstring);
string readnamesquery = "select cwFullTitle from tbCowWorkers";
cn.Open();
SqlCommand cmd = new SqlCommand(readnamesquery, cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
ddlUsers.DataSource = dt;
ddlUsers.DataValueField = "cwFullTitle";
ddlUsers.DataTextField = "cwFullTitle";
ddlUsers.DataBind();
cn.Close();
}
//Inserting Item to another table by selected index change.
protected void ddlUser_SelectedIndexChanged(object sender, EventArgs e)
{
//Checking If it's not the default value.
if(ddlUser.SelectedIndex != -1){
// insert selected value to database
SqlConnection cn = new SqlConnection(GlobalData.connectionstring);
string registerQuery = "insert into Depot (dTdeliveryName) values
(N'"+ddlUsers.SelectedValue.ToString()+"')";
SqlCommand cmd = new SqlCommand(registerQuery, cn);
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}
}
i try to load values from sql database to combobox and after button click i want to save selected value of combobox to variable.
This is my code:
SqlConnection con = new SqlConnection(connectionstring);
con.Open();
string strCmd = "select id,Prijmeni from Osoba";
SqlCommand cmd3 = new SqlCommand(strCmd, con);
SqlDataAdapter da = new SqlDataAdapter(strCmd, con);
DataTable dt = new DataTable();
da.Fill(dt);
comboBox1.DataSource = dt;
comboBox1.DisplayMember = "Prijmeni";
comboBox1.ValueMember = "id";
comboBox1.Enabled = true;
cmd3.ExecuteNonQuery();
con.Close();
private void Ulozit_Click(object sender, EventArgs e)
{
//How i could save selected value of combobox to variable Value1 ???
}
Have you any ideas please?
You can save the selected value by:
var Value1 = comboBox1.SelectedValue;
private void Form1_Load(object sender, EventArgs e)
{
OleDbConnection con = new OleDbConnection(constr);
OleDbCommand cmd = new OleDbCommand("select project_name, ID from tb_project", con);
con.Open();
OleDbDataReader DR = cmd.ExecuteReader();
DataTable table = new DataTable();
table.Load(DR);
combo_status.DataSource = table;
combo_status.DisplayMember = "project_name";
combo_status.ValueMember = "ID";
combo_status.Text = "Select Project Name";
}
private void btnSave_Click_Click(object sender, EventArgs e)
{
OleDbConnection con = new OleDbConnection(constr);
con.Open();
OleDbCommand cmd = new OleDbCommand("Insert Into tb1(name) Values (#name)", con);
cmd.Parameters.AddWithValue("name", combo_status.SelectedValue);
cmd.ExecuteNonQuery();
con.Close();
MessageBox.Show("Inserted sucessfully");
}
In the first class i have a combobox and i am fetching its value from database and i have shown "Select Project Name" on page load in combobox.I want to insert its value only when user selects option from dropdown and insert nothing if user did not choose any option.
Now the problem is that the first name in the dropdown gets inserted on button click.without choosing any option.I want that if user did not choose any name value from dropdown nothing should get inserted.
can anyone help me..?
Assuming that datatype of ID column is int:
private void Form1_Load(object sender, EventArgs e)
{
OleDbConnection con = new OleDbConnection(constr);
OleDbCommand cmd = new OleDbCommand("select project_name, ID from tb_project", con);
con.Open();
OleDbDataReader DR = cmd.ExecuteReader();
DataTable table = new DataTable();
table.Load(DR);
//begin adding line
DataRow row = table.NewRow();
row["project_name"] = "Select Project Name";
row["ID"] = 0;
table.Rows.InsertAt(row, 0);
//end adding line
combo_status.DataSource = table;
combo_status.DisplayMember = "project_name";
combo_status.ValueMember = "ID";
combo_status.Text = "Select Project Name";
}
private void btnSave_Click_Click(object sender, EventArgs e)
{
if(combo_status.SelectedValue == 0)
{
return; //do nothing if user didn't select anything in combobox, you can change this line of code with whatever process you want
}
OleDbConnection con = new OleDbConnection(constr);
con.Open();
OleDbCommand cmd = new OleDbCommand("Insert Into tb1(name) Values (#name)", con);
cmd.Parameters.AddWithValue("name", combo_status.SelectedValue);
cmd.ExecuteNonQuery();
con.Close();
MessageBox.Show("Inserted sucessfully");
}
Hope this will help you
private void Form1_Load(object sender, EventArgs e)
{
string Sql = "select project_name from tb_project";
OleDbConnection con = new OleDbConnection(constr);
OleDbCommand com = new OleDbCommand(Sql, con);
con.Open();
OleDbDataReader DR = com.ExecuteReader();
while (DR.Read())
{
combo_status.Items.Add(DR[0]);
}
con.Close();
}
in this code i am fetching project name from a table in database and showing them in combobox but what i want is that in this is that in the table from where i am fetching project name there is a project id corresponding to that name...so i want project name to be displayed in combox and when i click on submit then it should insert project id corresponding to the project name choosen in combobox so how can i do that.....
Try this :
string Sql = "select project_name, project_id from tb_project";
con = new OleDbConnection(constr);
com = new OleDbCommand(Sql, con);
con.Open();
OleDbDataReader DR = com.ExecuteReader();
DataTable table = new DataTable();
table.Load(dr);
combo_status.DataSource = table;
combo_status.DisplayMember = "project_name";
combo_status.ValueMember= "project_id";
As per my understanding, you want to insert the project id of the selected project name in some other table. To accomplish this you can use following code:
private void Form1_Load(object sender, EventArgs e)
{
string Sql = "select project_id, project_name from tb_project";
OleDbConnection con = new OleDbConnection(constr);
OleDbCommand com = new OleDbCommand(Sql, con);
con.Open();
DataSet ds = new DataSet();
OleDbDataAdapter da = new OleDbDataAdapter(com);
da.Fill(ds);
combo_status.DataSource = ds.Tables[0];
combo_status.DisplayMember = "project_name";
combo_status.ValueMember = "project_id";
com.Dispose();
con.Close();
}
In this way you will find the project name using combo_status.SelectedText and you will find the project id using combo_status.SelectedValue. Now you can use it anywhere you want.
Use DisplayMember and ValueMember Of Combobox
// Fetch Both Project Name and Project Id
string Sql = "select project_name, project_id from tb_project";
con = new OleDbConnection(constr);
com = new OleDbCommand(Sql, con);
con.Open();
OleDbDataReader DR = com.ExecuteReader();
DataTable dt;
dt.Load(Dr);
combo_status.DataSource = dt; //Check it this works or not
combo_status.DisplayMember = "project_name";
combo_status.ValueMember= "project_id";
To get Project_id of Selected project_name
Int64 varproject_Id = Convert.ToInt64(combo_status.SelectedValue);
try this
while (DR.Read())
{
combo_status.Items.Add(DR.GetValues(0).toString());
}
I have two related comboboxes, combobox1 populate the items of combobox2. In combobox1 selectIndexChanged event I have this code but i have error Unknown column 'System.Data.DataRowView' in 'where clause'.
I tried to put this code in the SelectionChangeCommitted at first selection, it populate the right items, but my second selection i have error in comboBox2.Items.Clear(); states Items collection cannot be modified when the DataSource property is set. :( what to do.?
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
string sql;
if (comboBox1.SelectedIndex >= 0)
{
comboBox2.Items.Clear();
MySqlConnection conn = new MySqlConnection(sqlString);
MySqlDataAdapter adapter = new MySqlDataAdapter();
sql = "SELECT brgyname,idbrgy from barangay where idmun=" + comboBox1.SelectedValue;
adapter.SelectCommand = new MySqlCommand(sql, conn);
DataTable cbBrgy = new DataTable();
adapter.Fill(cbBrgy);
comboBox2.DataSource = cbBrgy;
comboBox2.DisplayMember = "brgyname";
comboBox2.ValueMember = "idbrgy";
}
}
Here's how i populate combobox1
private void cbMun()
{
MySqlConnection conn = new MySqlConnection(sqlString);
MySqlDataAdapter adapter = new MySqlDataAdapter();
adapter.SelectCommand = new MySqlCommand("SELECT munname,idmun from municipality", conn);
DataTable cbMun = new DataTable();
adapter.Fill(cbMun);
comboBox1.DataSource = cbMun;
comboBox1.DisplayMember = "munname";
comboBox1.ValueMember = "idmun";
}
while cbMun function is filling the combobox it will call combobox selected index change event directly , so to work around this define bool value comboisloading = true and modify your code such like below :
private void cbMun()
{
MySqlConnection conn = new MySqlConnection(sqlString);
MySqlDataAdapter adapter = new MySqlDataAdapter();
adapter.SelectCommand = new MySqlCommand("SELECT munname,idmun from municipality", conn);
DataTable cbMun = new DataTable();
adapter.Fill(cbMun);
comboBox1.DataSource = cbMun;
comboBox1.DisplayMember = "munname";
comboBox1.ValueMember = "idmun";
comboisloading = false;
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboisloading)
return;
string sql;
if (comboBox1.SelectedIndex >= 0)
{
comboBox2.Items.Clear();
MySqlConnection conn = new MySqlConnection(sqlString);
MySqlDataAdapter adapter = new MySqlDataAdapter();
sql = "SELECT brgyname,idbrgy from barangay where idmun=" + comboBox1.SelectedValue;
adapter.SelectCommand = new MySqlCommand(sql, conn);
DataTable cbBrgy = new DataTable();
adapter.Fill(cbBrgy);
comboBox2.DataSource = cbBrgy;
comboBox2.DisplayMember = "brgyname";
comboBox2.ValueMember = "idbrgy";
}
}
I just placed my code in comboBox1_SelectionChangeCommitted not in comboBox1_SelectedIndexChanged event since comboBox1.SelectedValue is still not generated not unless the user committed its changes to the items. Also my Items collection cannot be modified when the DataSource property is set error from comboBox2.Items.Clear(); i just deleted this line of code. I still clears and replace my combobox2 items properly. Hmm.. Since i used to clear comboboxes in vb..I wonder.
private void comboBox1_SelectionChangeCommitted(object sender, EventArgs e)
{
string sql;
MySqlConnection conn = new MySqlConnection(sqlString);
MySqlDataAdapter adapter = new MySqlDataAdapter();
sql = "SELECT brgyname,idbrgy from barangay where idmun=" + comboBox1.SelectedValue;
adapter.SelectCommand = new MySqlCommand(sql, conn);
DataTable cbBrgy = new DataTable();
adapter.Fill(cbBrgy);
comboBox2.DataSource = cbBrgy;
comboBox2.DisplayMember = "brgyname";
comboBox2.ValueMember = "idbrgy";
}