c# - C# - 用 DataTable 填充组合框

Question

我习惯于使用有大量示例可用的 Java。由于各种原因，我不得不切换到 C# 并尝试在 SharpDevelop 中执行以下操作：

// 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<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";

有人会假设在下拉列表中看到一些值，但它是空的。请告诉我我做错了什么;(

编辑： mnuActionLanguage.ComboBox.DataBind() 是我在网上也找到的，但在我的情况下它不起作用。

解决方案

mnuActionLanguage.ComboBox.BindingContext = this.BindingContext;

最后解决了问题！

score 34 · Accepted 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 < 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;

score 9 · Accepted 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;

score 6 · Accepted 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";

score 3 · Accepted 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.

score 1 · Accepted Answer

几点：

1) "DataBind()" 仅适用于 Web 应用程序（不是 Windows 应用程序）。

2）你的代码看起来很“JAVAish”（不是坏事，只是观察）。

试试这个：

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.

score 0 · Accepted Answer

这条线

mnuActionLanguage.ComboBox.DisplayMember = "Lang.Language";

是错的。将其更改为

mnuActionLanguage.ComboBox.DisplayMember = "Language";

它会工作（即使没有 DataBind()）。

c# - C# - 用 DataTable 填充组合框

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